'anti-homosexual' originates from the prefix 'anti-' (from Greek 'antí-') meaning 'against' combined with 'homosexual', where 'homosexual' itself is formed from Greek 'homō-' ('same') and Latin 'sexus' ('sex').

'homosexual' was coined in the 19th century (attested in German medical and social discourse) from Greek and Latin roots and entered English in the late 19th century; 'anti-' has been used as a productive English prefix since classical times, and the compound 'anti-homosexual' developed by combining the two elements to mean opposition to homosexuality.

Initially, the parts meant 'against' + 'same-sex/sexual' at formation; the compound's meaning has remained focused on opposition to homosexuality, now often carrying the connotation of prejudice or hostility.