'imperfectly-formed' is a compound word from 'imperfectly' and 'formed'. 'Imperfectly' comes from 'imperfect' + '-ly', and 'formed' is the past participle of 'form'. 'Imperfect' originates from Latin 'imperfectus', where 'im-' meant 'not' and 'perfectus' meant 'completed'.

'Imperfectus' in Latin became 'imperfect' in Middle English, and 'imperfectly' was formed by adding '-ly'. 'Formed' comes from Old French 'former', from Latin 'formare'. The compound 'imperfectly-formed' is a modern English construction.

Initially, 'imperfectus' meant 'not completed', and 'formare' meant 'to shape'. The phrase 'imperfectly-formed' has always meant 'not completely or properly shaped'.