'feminise' originates from Modern English, specifically formed from the adjective 'feminine' plus the verb-forming suffix '-ise' (from French '-iser'), where 'feminine' ultimately traces to Latin 'femina' meaning 'woman' and '-ise' meant 'to make or become'.

'feminise' changed from Latin and Old French roots: Latin 'femina' produced Old French and Middle English forms like 'feminine', and English later formed the verb (also seen as 'feminize') by adding the productive verb suffix '-ize/-ise' to 'feminine'.

Initially it meant 'to make or become womanlike' or 'to assign female gender'; over time it has come to cover both giving feminine characteristics and changing grammatical or social forms to the feminine.