'Messier' (as the comparative adjective) originates from English, specifically from the adjective 'messy' + the comparative suffix '-er', where 'messy' comes from the noun 'mess' (Middle English 'messe' from Old French 'mes'), originally meaning 'a portion (of food)'.

'Messier' (comparative) was formed from the adjective 'messy'. 'Messy' developed from Middle English 'messe' (Old French 'mes') meaning a portion or serving; over time 'mess' shifted to mean disorder, giving English 'mess' and then 'messy', and finally the comparative form 'messier'. Separately, the surname 'Messier' is of French origin as a family name (seen in Charles Messier).

Initially 'mess' referred to a portion or serving (of food); its sense shifted toward disorder, and 'messy' came to mean 'untidy', with 'messier' now meaning 'more untidy'.