WordWeb Online

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

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