- 1causing or ending in death a fatal accident/blow/illness a potentially fatal form of cancer If she gets sick again, it could prove fatal. compare mortal
- 2causing disaster or failure a fatal error/mistake Any delay would be fatal. There was a fatal flaw in the plan. It would be fatal to try and stop them now.
NAmE//ˈfeɪt̮l̩i//
adverb fatally injured/wounded The plan was fatally flawed from the start.See fatal in the Oxford Advanced Learner's DictionaryCheck pronunciation: fatal