Source : Webster's Revised Unabridged Dictionary (1913)

Emaciation \E*ma`ci*a"tion\, n. [Cf. F. ['e]maciation.]
   1. The act of making very lean.

   2. The state of being emaciated or reduced to excessive
      leanness; an excessively lean condition.

Source : WordNet®

emaciation
     n : extreme leanness (usually caused by starvation or disease)
         [syn: {bonyness}, {gauntness}, {maceration}]