'anti-casteist' originates from modern English, formed by the prefix 'anti-' (from Greek 'anti' meaning 'against'), the noun 'caste' (from Portuguese 'casta' meaning 'race, lineage'), and the suffix '-ist' (from Greek '-istēs' via Latin/French meaning 'one who advocates or practices').

'anti-casteist' is a compound created in contemporary English by joining 'anti-' + 'caste' + '-ist'. The element 'caste' entered English from Portuguese 'casta' (ultimately from Latin roots) and was incorporated into compound formations in modern usage to indicate opposition to caste systems.

The components originally conveyed 'against' + 'caste (a social grouping)'; together they have come to mean 'opposed to the caste system or caste-based discrimination' without additional metaphorical shifts.