'anti-rebel' originates from Modern English, specifically by combining the prefix 'anti-' (from Greek 'anti-' where 'anti-' meant 'against') and 'rebel' (from Old French 'rebelle', ultimately from Latin 'rebellis').

'rebel' changed from Old French 'rebelle', which came from Latin 'rebellis' (from re- 'again' + bellum 'war') and eventually became the modern English word 'rebel'; the prefix 'anti-' entered English via Greek/Latin formation and has been used in Modern English compounds such as 'anti-...' to mean 'against'.

Initially the elements meant 'against' (anti-) and 'one who takes up arms or resists' (rebel); combined in Modern English the compound now specifically denotes someone or something opposed to rebels or rebellion.