'well-phrased' is a compound formed from 'well' + the past participle 'phrased'. 'well' originates from Old English, specifically the word 'wel', where 'wel' meant 'well, thoroughly'; 'phrase' ultimately originates from Greek via Latin and Old French, specifically Greek 'phrasis' (from the verb 'phrazein'), where 'phrazein' meant 'to show, declare'.

'phrase' entered English via Old French and Latin forms (Latin/Greek 'phrasis' → Old French 'phrase' → Middle English 'phrase'), and the past participle 'phrased' developed from the verb 'to phrase'; combined with the adverb 'well' (Old English 'wel'), the compound 'well-phrased' came to be used in Modern English to describe something expressed skillfully.

Originally, Greek 'phrazein' meant 'to show or declare' and 'phrasis' referred to the act of speaking; over time 'phrase' shifted to mean a particular way of expressing something, and combined with 'well' it evolved into the modern sense 'expressed skillfully or elegantly'.