'antimoniated' ultimately derives from the element name 'antimony' (English), itself from New Latin 'antimonium' (the name for the element), combined with the chemical verb-forming suffix '-ate' and the past participle suffix '-ed'.

'antimonium' (New Latin) passed into Old French as 'antimoine' (or Middle French 'antimoine') and into Early Modern English as 'antimony'; chemical nomenclature later produced 'antimoniate' (to form a salt or compound with antimony), which yielded the past form and adjective 'antimoniated'.

Originally referring simply to the element 'antimony' or things relating to it, the term evolved in chemical usage to mean 'having been treated with or combined with antimony', the sense preserved in 'antimoniated'.