'life-threatening' originates from the combination of 'life' and 'threatening', where 'life' refers to existence and 'threatening' means causing danger or harm.

'life-threatening' evolved from the combination of the words 'life' and 'threaten' in English, eventually forming the modern adjective 'life-threatening'.

Initially, it meant 'posing a threat to life', and this meaning has remained consistent in modern usage.