'antimonite' originates from Modern English, specifically formed from the noun 'antimony' plus the mineral/chemical suffix '-ite' (used to name minerals or salts).

'antimony' entered English via Old French 'antimoine' and Medieval Latin 'antimonium'; the English mineral/chemical formation '-ite' (from Greek '-ites' by way of Latin/French) was appended to create 'antimonite'.

Initially the term was applied to a naturally occurring antimony mineral (an older name for stibnite) and later or more generally to salts/compounds of antimonous acid; over time its use narrowed in chemistry to refer to antimony(III) salts while the mineral name fell out of common use.