dead giveaway

something that reveals a fact or an intention completely. The car in the driveway was a dead giveaway that someone was at home.

Name	Pronounced	Usage
Simon	SIE-mən (English), see-MAWN (French), ZEE-mawn (German), SEE-mawn (Dutch)	English, French, Swedish, Norwegian, Danish, German, Dutch, Hungarian, Slovene, Romanian, Macedonian
Pierre	[pi(:)'ɛə]
Odilie	o-DEE-lee-ə	German (Archaic)
Servius	SER-wi-uws	Ancient Roman
Godwin	['gɔdwin]
Babatunde	-	Western African, Yoruba