Definition of reactive in US English:



  • 1Showing a response to a stimulus.

    ‘pupils are reactive to light’
    • ‘Individuals who have experienced severe trauma would therefore be more likely to be more reactive to pain.’
    • ‘I was a bit surprised to read the reactive / defensive response of some of my classmates.’
    • ‘The reactive response is when my ego is offended.’
    • ‘Thus the direction and depth of our reactive attitudes and moral responses track the type of behavior we are responding to, and help encourage or discourage it, depending on our interests.’
    • ‘Are all persons equally reactive or vulnerable to negative interpersonal events?’
    • ‘Steering was nicely reactive though a little too light at higher speeds.’
    • ‘The pupils should be equal, round, and reactive to light in both eyes.’
    • ‘Generally speaking, it is a reactive organisation, which responds to demand.’
    • ‘Among sensation seekers, Zuckerman has found, dopamine levels are low and very reactive to stimulation.’
    • ‘Today the masculinity crisis is generally seen as a negative reactive response to feminism, to the growing independence of women, and to the blending of gender roles.’
    • ‘The less emotionally reactive the couple becomes, the less the therapist structures the enactment.’
    • ‘Light steering was reactive enough to inspire confidence while firm handling and suspension remained settled around S-bends and potholes.’
    • ‘The Internet poses several potential challenges to the regime that provoke a reactive state response.’
    • ‘Think about your reactive responses in the past to the same or similar experiences.’
    • ‘Another component of reactive aggression is physiological response.’
    • ‘When we see someone in such a light as this, all our reactive attitudes tend to be profoundly modified.’
    • ‘Often mydriasis occurs with the pupils poorly reactive or non-reactive to light.’
    • ‘Is the measles virus reactive to ultra violet light?’
    • ‘Again, Gibbins accounts for the history of populism in western Canada by suggesting that it is largely a reactive response to the inadequacy of regional representation in the federal government.’
    • ‘One study thermally characterized the reactive hyperemic response of healthy skin.’
    responsive to, quick to respond to, sensitized to, reactive to, sentient of
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    1. 1.1 Acting in response to a situation rather than creating or controlling it.
      ‘a proactive rather than a reactive approach’
      • ‘Proactive and reactive aggression were assessed when the boys were 13 years of age.’
      • ‘Mr McCormick admits maintenance has been largely reactive and has been concentrated on health and safety matters.’
      • ‘This means that most types of event will generate an alert rather than a reactive response.’
      • ‘In a crisis like that, a company changes its whole behavior and becomes reactive in nature.’
      • ‘The longitudinal correlates of proactive and reactive aggression in children also seem to differ.’
      • ‘Merina Salandy-Brown, a media consultant who worked with the BBC for 18 years, said the draft code was reactive rather than proactive.’
      • ‘It seems to be that it is time for proactive rather than reactive support to be given to Dean John.’
      • ‘The key is to be proactive rather than reactive taking a firm stance before the situation gets out of hand.’
      • ‘Getting tough with the community, being proactive and not always reactive, with proper controls will also help.’
      • ‘At present this emergent ‘citizens' media’ is reactive rather than pro-active, but things could change quickly.’
      • ‘The leaders who built enduring great companies showed a creative inside-out approach rather than a reactive outside-in approach.’
      • ‘Such methods would enable dietitians involved in biotechnology education to take a proactive rather than a reactive approach.’
      • ‘Many form oils on the market are blends of passive and reactive agents designed for specific purposes.’
      • ‘You can make information available proactively and deliver reactive messages that address specific events as they develop.’
      • ‘But we cannot allow them to shift us into a purely reactive mode.’
      • ‘The existence of reactive stalking raises a number of problems that require our attention.’
      • ‘This is a recognition that we need to be more proactive rather than reactive as we have been up to now.’
      • ‘Clinton, they claimed, was reactive and haphazard rather than proactive and forceful.’
      • ‘Much of Cuba's Internet control strategy has entailed reactive state responses to the challenges outlined above.’
      • ‘At other times, the president is reactive rather than proactive.’
      quick to react, receptive, open to suggestions, amenable, flexible, accessible, approachable, forthcoming, sensitive, perceptive, sympathetic, well disposed, susceptible, impressionable, open, alive, awake, aware
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    2. 1.2 Having a tendency to react chemically.
      ‘nitrogen dioxide is a highly reactive gas’
      • ‘Tin is less reactive than the metal it covers, protecting the underlying metal from corrosion.’
      • ‘Amides tend to be somewhat less reactive, but are also subject to hydrolysis and analogous reactions.’
      • ‘At room temperature, formaldehyde is an extremely reactive colorless gas with a suffocating odor.’
      • ‘Since they have two electrons that they must lose, they are not quite as reactive as the alkali metals.’
      • ‘Zinc tends to be much less reactive with oxygen than are the metals that are galvanized.’
      • ‘The element is not very reactive chemically, although it does dissolve in most acids.’
      • ‘A molecule's functional group is the chemically reactive portion, or segment, of an organic chemical molecule.’
      • ‘The addition of scavengers suggests that reactive oxygen species caused this bacterial growth inhibition.’
      • ‘Although ketones are not as reactive as aldehydes, they are also important intermediates in the synthesis of many compounds.’
      • ‘In addition, chemically reactive derivatives of ppGpp have been synthesized and used for cross-linking experiments.’
      • ‘The rounded cables are UV reactive and come in the Round Cable box.’
      • ‘And by making the particles chemically reactive, scientists are building exquisitely sensitive sensors that can detect individual molecules.’
      • ‘The major risk comes from the formation of reactive oxygen intermediates during normal oxygen metabolism.’
      • ‘Ozone is produced when sunlight triggers chemical reactions involving reactive hydrocarbons and nitrogen oxides.’
      • ‘Fluorine was the most difficult halogen to isolate because it is so chemically reactive.’
      • ‘In addition, the very reactive singlet oxygen can be generated by an input of energy.’
      • ‘Monomers involved in condensation reactions typically contain two reactive groups within the molecule.’
      • ‘While not as reactive as the alkali metals, this family knows how to make bonds very easily.’
      • ‘Derived chiefly from petroleum and coal tar, aromatic hydrocarbons tend to be reactive.’
      • ‘Because free radicals are highly reactive, they are capable of damaging the body.’
    3. 1.3Physiology Showing an immune response to a specific antigen.
      • ‘Arrows indicate cells reactive to the zeatine specific antibodies.’
      • ‘Traditional antivirus protection is very reactive in nature.’
      • ‘Equivocal or weakly reactive immunohistochemical stains may require further testing to make the diagnosis of mesothelioma.’
      • ‘Several methods are available to prevent the formation of preformed reactive antibodies to HLA antigens.’
      • ‘Eyebright appears to make your immune system less reactive to airborne allergens.’
    4. 1.4 (of a disease or illness) caused by a reaction to something.
      ‘reactive arthritis’
      ‘reactive depression’
      • ‘Differentiating reactive airway dysfunction syndrome from other types of work-related asthma is generally straightforward.’
      • ‘In novice marijuana users, rarely in regular users, marijuana may precipitate reactive or neurotic depressions.’
      • ‘Reactive arthritis occurs most frequently in men 20 to 40 years old.’
      • ‘He told me that he has been diagnosed as suffering from reactive depression and is currently being treated for that by a psychiatrist.’
      • ‘Three children had reactive inflammatory arthritis.’
      • ‘All of them apparently tested positive for sexually acquired reactive arthritis, or SARA.’
      • ‘This unusual reactive lesion of the gastric mucosa has only rarely been described and has been termed Russell body gastritis.’
      • ‘Two forms of occupational asthma are recognized: reactive airway dysfunction syndrome and allergic occupational asthma.’
      • ‘For those patients with reactive airway disease, pre-medication should be considered.’
      • ‘Hilar lymphadenopathy with other pulmonary infiltrates is infrequent and thought to represent reactive hyperplasia.’
      • ‘Early identification and treatment of chlamydia may slow the progression of reactive arthritis.’
      • ‘The histologic causes of these false-positive lymph nodes were granuloma, reactive inflammation, and anthracosis.’
      • ‘He may be suffering from reactive depression resulting from traumatic events whilst living in Kosovo.’
      • ‘Patients may suffer from anxiety, depression and reactive adjustment disorders.’
      • ‘Reiter's syndrome is a form of reactive arthritis, an inflammation of the joints that occurs in response to infection.’
      • ‘The defence presented evidence that Juman suffered from cannabis-induced psychotic disorder, reactive depression and schizophrenia.’
      • ‘The etiology of a pulmonary exacerbation is likely a variety of airway insults including respiratory viral infections, reactive airway disease, and pollutants.’
      • ‘Therefore, elevation of the control site temperature helped mask temperature increases caused by reactive hyperemia or inflammation in some cases.’
      • ‘I diagnosed him, your Honour, as suffering from a reactive agitated depressive disorder, which was severe in type.’
      • ‘The most commonly encountered are Russell and butcher bodies in lymphomas, multiple myeloma, and some reactive or immunologic diseases.’
    5. 1.5Physics Relating to reactance.
      ‘a reactive load’
      • ‘If this angle is zero degrees, the load is purely resistive; if the angle is not zero, there is some reactive loading, or additional storage in the system.’
      • ‘Generator tripping must be technically and contractually feasible, and the reactive power devices must be in place.’
      • ‘It is important to remember that any reactive load will produce standing waves on the line.’
      • ‘If active and reactive power are not properly balanced, voltage collapse may occur in one part of the system and could propagate system failure.’
      • ‘There are separate accumulators for generator tripping and 500-kV reactive power compensation switching for this algorithm as well.’