'loyal' originates from Old French, specifically the word 'leial' (or 'loial'), where the root implied 'faithful' or 'true.'

'leial' (Old French) changed into Middle English forms like 'loial' and eventually became modern English 'loyal.'

Initially, it meant 'lawful' or 'appropriate' in senses related to legal/faithful status but evolved into the primary sense of 'faithful, faithful in allegiance' used today.