A Franco-English hybrid: 'beauty' (Old French 'bealté,' from Latin 'bellus') + the native English suffix '-ful' — literally 'full of beauty.'
Pleasing the senses or mind aesthetically; of a very high standard of attractiveness, excellence, or skill.
From Middle English 'beauteful' (full of beauty), composed of 'beauty' (from Anglo-Norman 'beauté,' from Old French 'bealté,' 'beltet,' from Vulgar Latin *bellitātem, accusative of *bellitās, from Latin 'bellus,' meaning 'pretty, handsome, charming, fine') and the native English suffix '-ful' (full of, characterized by). Latin 'bellus' is a diminutive of an older form related to 'bonus' (good), from Old Latin 'duenos,' from PIE *dew-eno- (to do, to show favor, to revere). The word 'beautiful' is thus a hybrid — a French-derived noun fused with a
English 'beautiful' is a Franco-English hybrid — a French root with an English suffix. If it had been formed entirely from French, it would be something like 'beauteous' (which does exist but sounds archaic). If it had been entirely English, it might be 'fairful' (which was never coined). The hybrid nature of 'beautiful' perfectly embodies the mixed character of the English vocabulary.