surefire

[shoo r-fahyuh r, shur-] /ˈʃʊərˌfaɪər, ˈʃɜr-/
adjective
1.
sure to work; foolproof:
a surefire moneymaking scheme.
Origin
1915-20; sure + fire
British Dictionary definitions for sure-fire

sure-fire

adjective
1.
(usually prenominal) (informal) certain to succeed or meet expectations; assured
Word Origin and History for sure-fire

surefire

adj.

also sure-fire, by 1864, American English, from sure + fire (v.). Originally of rifles.

Slang definitions & phrases for sure-fire

sure-fire

adjective

Unfailing; certain to succeed, happen, etc: His election is a sure-fire thing (1901+)