'unavoidability' originates from the combination of 'un-' meaning 'not', 'avoid' from Old French 'eviter', and the suffix '-ability' indicating a state or condition.

'unavoidability' evolved from the Middle English word 'unavoydable', which was derived from the Old French 'eviter', eventually forming the modern English word 'unavoidability'.

Initially, it meant 'not capable of being avoided', and this meaning has largely remained the same in modern usage.