tranquillize, tranquilise, tranquilize

t. & i. [Eng. tranquil; -ize.] A. Trans.: To make tranquil, calm, or quiet; to soothe; to allay when agitated; to compose, to calm, to make peaceful. "And tender Peace, and joys without a name, That, while they ravish, tranquillize the mind." Thomson: Castle of Indolence , ii. 19. B. In trans.: To grow tranquil, to cool down. "I'll try, as I ride in my chariot, to tranquillize ."Richardson: Clari a , v. 79.