A deficiency is an insufficient amount of something. If you feel sluggish and tired all day, you might have an iron deficiency, meaning you aren't eating enough iron-rich foods.

You are most likely to hear the word deficiency in regard to health, like a sleep deficiency. But you can use deficiency to describe other kinds of lack — a deficiency of fun that occurred while your friends were out of town. Deficiency also means a failure or shortcoming, like a deficiency in math class, which might result in a notice from school — known as a deficiency — being mailed to your home.

Definitions of deficiency
  1. noun
    lack of an adequate quantity or number
    synonyms: inadequacy, insufficiency
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    adequacy, sufficiency
    the quality of being sufficient for the end in view
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    exiguity, leanness, meagerness, meagreness, poorness, scantiness, scantness
    the quality of being meager
    deficit, shortage, shortfall
    the property of being an amount by which something is less than expected or required
    scarceness, scarcity
    a small and inadequate amount
    the quality of being slight or inadequate
    meagerness or poorness connoted by a superfluity of water (in a literary style as well as in a food)
    restricted to bare necessities
    oxygen deficit
    temporary oxygen shortage in cells resulting from strenuous exercise
    spareness, sparseness, sparsity, thinness
    the property of being scanty or scattered; lacking denseness
    dearth, paucity
    an insufficient quantity or number
    infrequency, rareness, rarity
    noteworthy scarcity
    type of:
    the relative magnitude of something with reference to a criterion
  2. noun
    the state of needing something that is absent or unavailable
    “water is the critical deficiency in desert regions”
    synonyms: lack, want
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    the state of being absent
    dearth, famine, shortage
    an acute insufficiency
    a deficiency or failure in neurological or mental functioning
    mineral deficiency
    lack of a mineral micronutrient that is essential for normal nutrition or metabolism
    the condition of being short of something
    stringency, tightness
    a state occasioned by scarcity of money and a shortage of credit
    absence by virtue of not occurring
    the state of being elsewhere than in particular place
    a deficiency of iron; results from inadequate iron in the diet or from hemorrhage
    type of:
    demand, need
    a condition requiring relief
Word Family

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