flameout I. \ˈ ̷ ̷ˌ ̷ ̷\noun (-s) Etymology:flame (II) + out : the cessation of operation of a jet aircraft engine (as through improper combustion or exhaustion of the fuel supply) — called also blowout II. noun 1.: a sudden downfall, failure or cessation < a business marked by overnight triumph and equally sudden flameouts — Todd Gold > 2.: a person whose successful career ends abruptly