'unequal-fruited' is a modern English compound formed from 'unequal' and 'fruited'. 'unequal' ultimately originates from Latin, specifically the word 'inaequalis', where the prefix 'in-' meant 'not' and 'aequalis' meant 'equal'. 'fruit' originates from Latin, specifically the word 'fructus', where it meant 'fruit, produce, enjoyment'.

'unequal' entered English via Old French (e.g. 'inegal') from Latin 'inaequalis' during the Middle English period; 'fruit' passed into English from Old French 'fruit', which in turn derived from Latin 'fructus'. The compound 'unequal-fruited' is a more recent formation created by joining the adjective 'unequal' with the past-participial adjective-form 'fruited' to describe botanical conditions.

The components originally meant 'not equal' (unequal) and 'fruit/produce' (fruit). Over time these retained their core senses, and the compound came to be used specifically to describe plants that bear fruits differing in size, shape, or development.