'antimetabolic' originates from the prefix 'anti-' (from Greek 'antí', meaning 'against') combined with 'metabolic', itself from Neo-Latin/Greek roots related to 'metabolism' (from Greek 'metabolē'/'metaballein').

'antimetabolic' was formed in modern scientific/medical English by joining 'anti-' + 'metabolic' (the latter coming into English via Latin/French from Greek 'metabolikos' and 'metaballein'), producing a compound used in 20th-century biomedical contexts.

Initially the elements meant 'against' (anti-) and 'relating to change/processing' (metabolic); together they evolved into the technical sense 'opposing or inhibiting metabolism' used in pharmacology and physiology.