tranquillizer

from WordNet (r) 3.0 (2006)

tranquillizer
    n 1: a drug used to reduce stress or tension without reducing
         mental clarity [syn: {tranquilizer}, {tranquillizer},
         {tranquilliser}, {antianxiety agent}, {ataractic drug},
         {ataractic agent}, {ataractic}]

from The Collaborative International Dictionary of English v.0.48

Tranquilizer \Tran"quil*i`zer\, Tranquillizer \Tran"quil*li`zer\
,  n.
   One who, or that which, tranquilizes.
   [1913 Webster] Tranquilizing

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