Source : Webster's Revised Unabridged Dictionary (1913)

Allayer \Al*lay"er\, n.
   One who, or that which, allays.

Source : WordNet®

allayer
     n : a person who reduces the intensity (e.g., of fears) and
         calms and pacifies; "a reliever of anxiety"; "an allayer
         of fears" [syn: {reliever}, {comforter}]