'frontiersman' originates from Middle English, built from 'frontier' (from Old French 'frontiere' meaning 'border, boundary') combined with Old English 'mann' meaning 'person'.

'frontiersman' developed from Middle English compounds of 'frontier' + 'man'; 'frontier' itself came into English via Old French 'frontiere' (meaning 'border') and earlier Latin/French roots, and was joined with the Old English 'mann' to form a term for a person of the frontier.

Initially, 'frontier' primarily meant a border or boundary; over time the compound 'frontiersman' came to denote a person who lives in, works on, or explores those borderlands—especially early settlers and explorers.