'gun-friendly' originates from modern English as a compound of the words 'gun' and 'friendly'. 'gun' originates from Middle English, specifically the word 'gunne', where the exact origin is uncertain (possibly from a personal name). 'friendly' originates from Old English, specifically the words 'freond' and 'freondlic', where 'freond' meant 'friend'.

'gun' developed into modern English from Middle English 'gunne' and later became the current form 'gun'. 'friendly' developed from Old English 'freondlic' through Middle English forms such as 'frendly' to modern 'friendly'. The compound 'gun-friendly' is a relatively recent formation in modern English, combining an object ('gun') with the adjective-forming element 'friendly'.

Initially, 'friendly' meant 'like a friend' or 'characteristic of a friend', and 'gun' referred simply to the weapon. Over time the compound 'gun-friendly' came to mean 'supportive of or permissive toward guns' rather than indicating personal friendliness.