- deficient, lacking, wanting - inadequate in amount or degree; "a deficient education"; "deficient in common sense"; "lacking in stamina"; "tested and found wanting"
Antonym: adequate (indirect, via inadequate)
- insufficient, deficient - of a quantity not able to fulfill a need or requirement; "insufficient funds"
- deficient, inferior, substandard - falling short of some prescribed norm; "substandard housing"
Antonym: standard (indirect, via nonstandard)