'anti-egoistic' originates from Greek and Latin elements: specifically the Greek prefix 'anti-' (from Greek 'ἀντί') meaning 'against', combined with the English adjective 'egoistic', which is built on Latin 'ego' meaning 'I'.

'anti-egoistic' developed in modern English as a compound of the productive prefix 'anti-' + the adjective 'egoistic' (which itself derives from 'egoism', a noun formed from Latin 'ego'). Over time English combined these elements to create the adjective 'anti-egoistic' to denote opposition to egoism.

Initially it literally meant 'against egoism'; over time it has been used more broadly to describe attitudes or actions that are unselfish, altruistic, or other-regarding rather than simply negating a philosophical position.