'gun-supporter' is a compound of 'gun' and 'supporter'. 'gun' originates from Middle English 'gunne' (originally referring to a cannon or large firearm), and 'supporter' comes from Old French/Anglo-Norman via Middle English from Latin roots ('soutenir' / 'supportare') meaning 'to hold up' or 'to carry'.

'gun' changed from Middle English 'gunne' (used for artillery and large firearms) to the modern English 'gun' (covering a range of firearms). 'supporter' developed from Old French/Latin forms into Middle English 'supporter' and then modern English 'supporter', shifting toward the sense 'one who advocates or backs' something.

Initially, 'gun' often referred to large firearms or cannons; over time it broadened to include hand-held firearms. 'supporter' originally meant someone who bears or upholds (physically) and evolved to mean someone who actively backs or advocates an idea or cause. Combined, 'gun-supporter' now means an advocate for gun ownership/rights.