'defeminise' originates from Latin, specifically the word 'femina', where 'femina' meant 'woman', combined with the Latin prefix 'de-' meaning 'remove' or 'reverse', and the English verb-forming suffix '-ise'.

'defeminise' changed through formation from the Late Latin root 'femina' into Old French and Middle English forms 'femin-' and the verb 'feminise', and in modern English the prefix 'de-' was added to produce 'defeminise'.

Initially related forms focused on 'making or relating to womanhood' (feminise); with the addition of 'de-' the modern verb came to mean 'removing or reversing feminine characteristics'.