tranquilize

Etymology

From Middle French tranquiliser. Analyzable as tranquil + -ize

verb

1. (transitive) To calm (a person or animal) or put them to sleep using a tranquilizer dart.
   The escaped lion was finally tracked down, tranquilized, and safely returned to the zoo.
   Miss Ratched shall line us all against the wall, where we’ll face the terrible maw of a muzzle-loading shotgun which she has loaded with Miltowns! Thorazines! Libriums! Stelazines! And with a wave of her sword, blooie! Tranquilize all of us completely out of existence. 1962, Ken Kesey, One Flew Over the Cuckoo’s Nest, New York: Dial, page 255
   When the public protests, confronted with some obvious evidence of damaging results of pesticide applications, it is fed little tranquilizing pills of half truth. 1962, Rachel Carson, chapter 2, in Silent Spring, Boston: Houghton Mifflin, page 13
2. (transitive, now literary) To make (something or someone) tranquil.
   1779, Frances Burney, Evelina, Dublin: Price, Corcoran et al., Volume 2, Letter 14, p. 87, […] with words of sweetest kindness and consolation, he soothed and tranquilised me.
   The column was placed under the orders of Major Renaud, who pushed up the road; fighting as occasion offered; tranquillizing the country by the very simple expedient of hanging everybody who showed signs of insubordination […] 1865, G. O. Trevelyan, chapter 5, in Cawnpore, London: Macmillan, page 322
   Supported by an impregnable sense of justice but still dangerously fuming, Lucia went back to her garden-room, to tranquillize herself with an hour’s practice on the new piano. 1931, E. F. Benson, chapter 4, in Mapp and Lucia
   But time had tranquillized Dina’s worries about the landlord. 1995, Rohinton Mistry, chapter 11, in A Fine Balance, Toronto: McClelland and Stewart, page 497
3. (intransitive, obsolete, rare) To become tranquil.