egoism

Origin:

late 18th century: from French égoïsme and modern Latin egoismus, from Latin ego 'I'

The words egoism and egotism are frequently treated as interchangeable, but there are distinctions which are worth noting. Egotism, the more commonly used term, means ‘the fact of being excessively conceited or absorbed in oneself’. Strictly speaking, egoism is a term used in Ethics to mean ‘a theory that treats self-interest as the foundation of moral behaviour’, although this sense is not dominant today; around 90 per cent of the citations for egoism in the Oxford English Corpus are for the meaning ‘excessive conceit’.