'self-styled' is a modern English compound of 'self' + the past participle 'styled' (from 'style'). 'Self' is Old English in origin (Proto-Germanic *selbaz) meaning 'one's own,' and 'style' traces to Latin 'stilus' via Old French, originally meaning a writing instrument and later 'manner, form'.

'styled' comes from the verb 'style' (Middle English from Old French estile/estyle), which in turn derives from Latin 'stilus.' The compound 'self-styled' arose in English by combining 'self' (Old English) with the participial use of 'style' to mean 'described or characterized by oneself.'

Originally 'style' related to a tool for writing and then to manner or form; 'self-styled' developed the sense 'styled or described by oneself,' and over time has come to mean 'self-proclaimed' with an implication of lacking official recognition.