Source : Webster's Revised Unabridged Dictionary (1913)

Tranquilizing \Tran"quil*i`zing\, Tranquillizing
\Tran"quil*li`zing\, a.
   Making tranquil; calming. `` The tranquilizing power of
   time.'' --Wordsworth. -- {Tran"quil*i`zing*ly} or
   {Tran"quil*li`zing*ly}, adv.