WordWeb Online

1. Inadequate in amount or degree
   "a deficient education"; "deficient in common sense";
   - lacking, wanting
    
2. Falling short of some prescribed norm
   "deficient housing";
   - inferior, substandard
    
3. Of a quantity not able to fulfil a need or requirement
   "deficient funds";
   - insufficient

See also: depleted, inadequate, jejune, lean, light, low, meager [N. Amer], meagerly [N. Amer], meagre [Brit, Cdn], meagrely [Brit, Cdn], nonstandard, poor, quantity, scant, scrimpy, short, shy, skimpy, stingy [informal], unequal