'comer' originates from English, formed from the verb 'come' plus the agent-forming suffix '-er'.

'come' comes from Old English 'cuman' (meaning 'to come'), from Proto-Germanic '*kumaną'; the agent noun 'comer' developed in Middle English by adding the suffix '-er' to denote 'one who comes.'

Initially it meant 'one who comes' and this basic meaning has largely remained, though it also appears in compounds (e.g. 'newcomer') and in colloquial senses like 'up‑and‑comer' (a promising person).