'anorexiant' originates from New Latin/modern formation, specifically from 'anorexia' + the agentive suffix '-ant', where the Greek prefix 'an-' meant 'without' and Greek 'orexis' meant 'appetite'.

'anorexiant' was formed in modern medical English from the noun 'anorexia' (from Greek 'an-' + 'orexis') with the suffix '-ant' to indicate an agent or causing substance; it entered English usage in late 19th to 20th century medical contexts.

Initially the root referred to the condition 'anorexia' (lack of appetite), and over time the derived noun 'anorexiant' came to mean specifically 'a substance that causes or produces loss of appetite', now commonly 'an appetite-suppressing drug'.