fatal

Universal Words adjective 1 causing or ending in death: a fatal accident / blow / illness * a potentially fatal form of cancer * If she gets ill again it could prove fatal. compareMORTAL 2 causing disaster or failure: a fatal error / mistake * Any delay would be fatal. * There was a fatal flaw in the plan. * It'd be fatal to try and stop them now. fatally adverb: fatally injured / wounded * The plan was fatally flawed from the start.