deficient in WordNet English dictionary

1. of a quantity not able to fulfill a need or requirement
   "insufficient funds"
   insufficient  deficient 
   
2. inadequate in amount or degree
   "a deficient education"; "deficient in common sense"; "lacking in stamina"; "tested and found wanting"
   deficient  lacking  wanting 
   
3. falling short of some prescribed norm
   "substandard housing"
   deficient  inferior  substandard