'appetite-suppressing' is a modern English compound formed from 'appetite' and the present participle 'suppressing'. 'appetite' originates from Latin, specifically the word 'appetitus', where 'appetere' meant 'to seek, desire'. 'suppress' originates from Latin, specifically the word 'supprimere', where 'sub-' (or 'sup-') meant 'under' and 'premere' meant 'to press'.

'appetite' changed from Old French 'appetit' (from Latin 'appetitus') into Middle English 'appetit' and eventually the modern English 'appetite'. 'suppress' came into English via Old French forms from Latin 'supprimere' ('supprimere' → Old French 'supprimer' → Middle English 'suppressen') and developed into modern 'suppress'. The compound 'appetite-suppressing' arose in modern English usage, especially in medical and nutritional contexts.

Initially, 'appetite' meant a general desire or longing and 'suppress' meant to press down; combined they originally meant 'to press down desire' and over time have come to specifically mean 'to reduce the desire to eat' in modern usage.