'ambush' (from which 'ambusher' and 'ambushers' are derived) originates from Old French, specifically the word 'embusche' or 'embusche', where the prefix 'em-' meant 'in' and 'busche' meant 'bush' or 'wood'.

'embusche' changed into Middle English forms such as 'embusch' or 'ambusch' and eventually became the modern English word 'ambush'; the agent noun 'ambusher' was formed from that base and 'ambushers' is its plural.

Initially it referred to a 'place of concealment' (a hiding place in the bushes), but over time the sense shifted to 'an attack from concealment' and then to a person who carries out such an attack.