'Tranquillizer' definitions:

Definition of 'tranquillizer'

From: WordNet
noun
A drug used to reduce stress or tension without reducing mental clarity [syn: tranquilizer, tranquillizer, tranquilliser, antianxiety agent, ataractic drug, ataractic agent, ataractic]

Definition of 'Tranquillizer'

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