'femaleish' originates from English, formed by the noun/adjective 'female' plus the adjectival suffix '-ish' (from Old English '-isc', Germanic), which conveys 'having the quality of' or 'somewhat like'.

'female' itself comes into Middle English from Old French 'femelle', which derived from Latin 'femella' (a diminutive of 'femina' meaning 'woman'). The suffix '-ish' comes from Old English '-isc' (related to German '-isch') and was used to form adjectives meaning 'of or pertaining to' or 'like'. The modern coinage 'femaleish' is a recent informal formation combining these elements.

Initially, the root 'female' meant 'of or relating to a woman' and that central sense remains; the combined form 'femaleish' took on the narrower, colloquial meaning 'somewhat female' or 'having some feminine traits'.