tranquilize

verb

tran·​quil·​ize ˈtraŋ-kwə-ˌlīz 

ˈtran-

variants or less commonly tranquillize

tranquilized also tranquillized; tranquilizing also tranquillizing

transitive verb

: to make tranquil or calm : pacify

especially : to relieve of mental tension and anxiety by means of drugs

intransitive verb

1

: to become tranquil : relax sense 1

2

: to make one tranquil

Synonyms of tranquilize

• calm
• soothe
• compose
• lull
• appease

Examples of tranquilize in a Sentence

They tranquilized the bear with a dart so that it could be safely moved to a different area.

at long last the crying baby was tranquilized by the steady rocking of her cradle

Recent Examples on the Web

Bourne Police assisted the Environmental Police in tranquilizing the bear, which was removed without incident. — Colleen Cronin, Boston Herald, 12 July 2026

The mountain lion was later safely and humanely tranquilized by a biologist with the California Department of Fish and Wildlife (CDFW), with assistance from wildlife officers and local law enforcement, according to NBC4 and the California Statewide Law Enforcement Association. — Moná Thomas, PEOPLE, 9 June 2026

That lion was also successfully tranquilized without any injuries. — Clara Harter, Los Angeles Times, 6 June 2026

In 2019, a young bear that had apparently trekked from the hills near Vacaville was tranquilized on campus. — Cecilio Padilla, CBS News, 15 May 2026

Word History

First Known Use

1623, in the meaning defined at transitive sense

Rhymes for tranquilize

• advertise
• aggrandize
• alibis
• alkalies
• alkalis
• amortize
• amplifies
• analyse
• analyze
• anywise
• authorize
• butterflies

Kids Definition

tranquilize

verb

tran·​quil·​ize

variants also tranquillize

ˈtraŋ-kwə-ˌlīz 

ˈtran-

tranquilized also tranquillized; tranquilizing also tranquillizing

: to make or become tranquil or relaxed

especially : to ease the nervous tension and anxiety of usually by means of drugs

Medical Definition

tranquilize

transitive verb

tran·​quil·​ize

variants or chiefly British tranquillize or tranquillise

ˈtraŋ-kwə-ˌlīz, ˈtran- 

tranquilized or chiefly British tranquilized or tranquilised; tranquilizing or chiefly British tranquilizing or tranquilising

: to make tranquil or calm

especially : to relieve of mental tension and anxiety by means of drugs

tranquilization noun

or chiefly British tranquillization or tranquillisation

ˌtraŋ-kwə-lə-ˈzā-shən, ˌtran-