Definition of poisonous in US English:



  • 1(of a substance or plant) causing or capable of causing death or illness if taken into the body.

    ‘poisonous chemicals’
    • ‘If you have young children think twice before planting poisonous trees.’
    • ‘The police sent the viscera of the woman for chemical examination to find out if the death was caused by some poisonous substance.’
    • ‘These pills are poisonous substances intending to end life.’
    • ‘The American courts for criminal procedure have stuck to a strong tradition of oppressing the fruits of the poisonous trees.’
    • ‘He also advised parents to lock up all detergents and poisonous substances, together with matches, lighters, pitch oil, guns and ammunition.’
    • ‘And some plants may transfer the poisonous chemicals to their food.’
    • ‘Detoxification once referred to the process of removing some specific poisonous substance from the body.’
    • ‘At least one other kind of fern is immediately poisonous, so such plants are not to be tasted at random.’
    • ‘A wayward camera does not help student wizards to catapult malevolent plants at poisonous mushrooms or send explosive cauldrons flying into barriers.’
    • ‘He further alleged that her in-laws made his sister drink milk laced with some poisonous substance.’
    • ‘Older brothers or sisters should be supervised when around a baby to stop them feeding tablets or other poisonous substances to the baby.’
    • ‘She allegedly consumed some poisonous substance.’
    • ‘There are no medical records anywhere in the world where people live with poisonous substances in their bodies.’
    • ‘These junkyards have to be removed as poisonous chemicals and substances flow into the river and the lake through these places.’
    • ‘All living organisms, including humans, are constantly exposed to foreign substances and poisonous chemicals or toxins.’
    • ‘The hemlock of the title refers to the evergreen tree, rather than to the poisonous herb that was the means of Socrates' forced suicide.’
    • ‘According to Lenin, as a consequence, the families are surviving on poisonous grass and wild mushrooms for the last four years.’
    • ‘The licence is available to any member of the public providing they adhere to a set of 14 conditions which include not removing soil from the land or planting any poisonous trees or shrubs on it.’
    • ‘It could be, and it's a doctrine that John knows well, the fruit of the poisonous tree.’
    • ‘Eating, for example, offers an avenue for ingesting tainted or poisonous food resulting in serious illness or death.’
    toxic, deadly, fatal, lethal, mortal, death-dealing, virulent, noxious, environmentally unfriendly
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    1. 1.1 (of an animal) producing poison as a means of attacking enemies or prey; venomous.
      ‘a poisonous snake’
      • ‘There will be some books on spotting bird species, and, if abroad, a rather worrying one on identifying poisonous insects and arachnids.’
      • ‘There are no poisonous snakes or insects and no malaria.’
      • ‘Dangerous and wild animals, like poisonous snakes and stinging ants, inhabited their rain forests.’
      • ‘I've been to Darwin and there's nothing there but poisonous spiders and snakes, so this man must be bored out of his head.’
      • ‘No, he likes the light here real good, but the puff adder is animal that has the longest fangs amongst any poisonous snake in the world.’
      • ‘They are also taught which animals to avoid like poisonous snakes, though they sometimes must learn on their own the hard way.’
      • ‘Then it occurred to me that Tuscany was no more infested with nasty poisonous creatures than the peaceful county of Norththamptonshire, where I reside without any fear at all.’
      • ‘Man-eating saltwater crocodiles lurk in nearby estuaries along with the deadly box jellyfish, the most poisonous creature on earth.’
      • ‘But the hole had its dangers; if the pot broke or cracked, the guerrilla could be attacked by poisonous spiders or snakes.’
      • ‘In case the Regent's Park buildings should be involved in an air raid, all the poisonous insects and snakes have been destroyed.’
      • ‘The poisonous insects are known to cause a horrible rash if tiny hairs from their bodies come into contact with a person's skin and they can also spark asthma and hay fever attacks.’
      • ‘The swamps are infested with poisonous snakes and fearsome insects with bites so strong they will either kill a man or drive him mad.’
      • ‘Primitive humans would have needed to avoid certain species of animals, as we do now, such as venomous snakes, poisonous frogs, tarantulas and wolves.’
      • ‘The tropical climate can be uncomfortable and brings the inevitable insects and poisonous creatures.’
      • ‘Lower in status were the scorpion-charmers, who used magic to rid an area of poisonous reptiles and insects.’
      • ‘Sea snakes are among the most poisonous creatures in the coral reef areas, described by scientists to rival a cobra.’
      • ‘Now, everyone knows the black snake is a poisonous creature.’
      • ‘The area abounded with poisonous snakes and insects, and I was continually amazed that none of the other children was bitten.’
      • ‘A snake or poisonous spider bites in a single spot, but the box jelly's venom enters a victim's body over a very large area.’
      • ‘From now on, special licences will be needed to own potentially dangerous pets, such as snakes or poisonous spiders.’
      venomous, deadly
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    2. 1.2 Extremely unpleasant or malicious.
      ‘there was a poisonous atmosphere at the office’
      • ‘The crack was good natured throughout, a pleasing change from some of the poisonous atmospheres we have all witnessed whenever matches between historical rivals take place.’
      • ‘For our choice would be starkly simple: to forgive the perpetrator or succumb to a poisonous thirst for vindication and revenge.’
      • ‘The atmosphere became so poisonous and paranoid and mixed up that towards the end neither Simpson nor Yates was really talking to me.’
      • ‘From its very first moments, Druick conjures up the poisonous atmosphere of a world ruled by fear and rumour where truth is merely the whim of an absolute monarch.’
      • ‘The US, because we are wealthy and powerful, is going to be slandered as a poisonous cultural wasteland.’
      • ‘Mark Malloch Brown claims that the atmosphere is growing poisonous as insiders in the UN's headquarters in New York attempt to stall reform.’
      • ‘The media, staffers and politicians feed off this poisonous atmosphere in a building that contains some fine art and architecture, but no soul and no warmth.’
      • ‘It also helps to create a poisonous atmosphere of suspicion and mistrust.’
      • ‘He talked at some length about how the atmosphere in D.C. was more poisonous than he had ever seen.’
      • ‘A number of parents will not take their children to the games because of the poisonous atmosphere.’
      • ‘From the outset, he has faced two obstacles: impossibly high expectations and a political atmosphere that can only be described as poisonous.’
      • ‘Jennette Fitzsimmons once said that there was a poisonous atmosphere within the party, it seems as though she is right’
      • ‘But the poisonous atmosphere is unlikely to help the trusts perform any better.’
      • ‘The atmosphere surrounding this dispute has gradually changed from fraught to poisonous.’
      malicious, malevolent, hostile, vicious, spiteful, bitter, venomous, evil-intentioned, ill-natured, vindictive, vengeful, vitriolic, rancorous, malign, malignant, pernicious, mean, nasty, harmful, hurtful, wounding
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Poisonous and venomous are not identical in meaning, although they are often used interchangeably. A poisonous animal or plant produces toxins that are harmful when the animal or plant is touched or eaten, whereas a venomous snake or other creature is able to inject venom by means of its fangs, spines, or stingers