Definition of deficient in English:



  • 1Not having enough of a specified quality or ingredient.

    ‘this diet is deficient in vitamin B’
    • ‘Johnstown Castle Research Centre indicated that more than one-third of the tillage land was seriously deficient in the critical trace elements, copper, zinc and manganese.’
    • ‘The summer growing season of kenaf corresponds with low quality forages deficient in protein in the Southeast.’
    • ‘The rapidly growing yearling is further jeopardized when twice daily feedings are already marginal or deficient in protein quality.’
    • ‘In fact many people in this country are deficient in vitamin D, which is made when sunlight hits the skin; children and old people especially are at risk, as it helps make strong healthy bones and teeth.’
    • ‘Over 2000 cases have been reported, reflecting the sensitivity of that growing gland to radioactive iodine, especially in children already deficient in iodine.’
    • ‘Farm research continues to revolve around NPK - nitrogen, phosphorous and potash - the three major plant nutrients that the soils are largely deficient in.’
    • ‘The scientists exposed mice deficient in both genes to a second carcinogen, DMN, which is also found in smoke but also in beer, fish meal and some preserved meats.’
    • ‘Phosphorus is the second most likely nutrient to be deficient in the soil for good corn yields.’
    • ‘A study of more than 600 elderly women has found that many are deficient in Vitamin D, a substance formed in the skin during exposure to the sun.’
    • ‘I told myself that my attitude, knowledge, and skill cost a patient's life and I was deficient in all those qualities that a doctor should have.’
    • ‘Bitumen - a form of heavy, thick oil laden with sulphur and deficient in hydrogen - can be refined into synthetic crude oil to make everything from gasoline to plastics.’
    • ‘Instead, if an adult is deficient in vitamin D and not getting enough calcium, calcium is drawn out from the bones, which causes osteoporosis.’
    • ‘A friend has told me there is some suggestion that children who suffer from attention deficit hyperactivity disorder may be deficient in iron.’
    • ‘An attack of inherited angioedema is treated with an injection of the C1 inhibitor, the substance that your body is deficient in.’
    • ‘A balanced diet ensures that the athlete will take in enough nutrients so that he or she will not be deficient in any of the electrolytes needed to maintain normal muscle function.’
    • ‘But, as children currently eat 50 per cent less fish than they did during the Second World War, it is thought that most youngsters are deficient in Omega 3.’
    • ‘Anyone with a history of, or predisposition towards, kidney stones should ensure their diet does not become deficient in calcium, as, by binding with oxalates in the gut, this mineral can help prevent stones forming.’
    • ‘The survey revealed that 30 per cent of the students were deficient in Vitamin A and B, and 17.75 per cent had iron deficiency.’
    • ‘And doctors also say an enzyme that helps breakdown sugar in the body, which is deficient in many diabetics, may also have an adverse effect on mental ability.’
    1. 1.1Insufficient or inadequate.
      ‘they trashed the legislation as deficient’
      • ‘She blames deficient preparation and insufficient commitment on the part of the school, but she also notes impediments in the exams themselves.’
      • ‘Both novels are occasionally limited by deficient character and plot development.’
      • ‘The failure of the Board to execute works is attributable to deficient planning with the result physical achievements fell short by 57 per cent.’
      • ‘The range at which identification can be reliably accomplished by these means, relative to weapon range, is marginal in daylight and deficient during periods of limited visibility.’
      • ‘In short, his conception of natural justice is deficient both in its theoretical structure and in its practical consequences.’
      • ‘Security management at the base was called deficient and lacking cohesion.’
      • ‘At that time, a forensic pathologist in New Zealand said that the service was short of staff, the overall funding was deficient, and there was no allocation to train people properly.’
      • ‘Similarly, she has not observed or complained about any deficient workmanship in the insulation and drywall and she believes that none exists with respect to her residence.’
      • ‘The major problems seem to be fragmentation, deficient base in popular constituencies and insufficient links between civic and political efforts.’
      • ‘In Being and Time Heidegger says that being along is a deficient or defective mode of being.’
      • ‘Women use them as a yardstick for measuring their own attractiveness, thus arriving at a warped perception of their own physical attributes as being hopelessly deficient.’
      • ‘The report accuses prosecutors of conducting deficient investigations or presenting inadequate evidence at the trials.’
      lacking, wanting, defective, inadequate, insufficient, limited, poor, scant
      defective, faulty, flawed, inadequate, imperfect, impaired, shoddy, scrappy, sketchy, weak, inferior, unsound, substandard, second-rate, poor, shabby, incomplete, leaving much to be desired
      View synonyms
  • 2dated, offensive Having mental disabilities.


Late 16th century (originally in the theological phrase deficient cause, denoting a failure or deficiency that has a particular consequence): from Latin deficient- failing from the verb deficere (see defect).