Definition of deficient
(Entry 1 of 2)
1
: lacking in some necessary quality or element
deficient in judgment bones deficient in calcium
2
: not up to a normal standard or complement (see complement entry 1 sense 1b(1)) : defective
deficient strength … rusted and aging pipes … abetted by deficient maintenance and sabotage.— Adam Nossiter
deficient
nounDefinition of deficient (Entry 2 of 2)
: a person or thing that is deficient
a mental deficient
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Merriam-Webster unabridged
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Time Traveler for deficient
The first known use of deficient was in 1581
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