'barfly' originates from English, specifically a compound of 'bar' and 'fly', where 'bar' meant 'a counter where drinks are served' and 'fly' was used metaphorically for 'a person who frequents a place'.

'barfly' was coined in the late 19th century as a compound of 'bar' + 'fly' (recorded use from the 1880s) and entered colloquial English without deriving from older Old English forms.

Initially, it referred specifically to someone who spent much time at a bar; this basic meaning has remained largely unchanged, though the word can carry humorous or mildly derogatory connotations.