egoism

Concise Oxford English Dictionary © 2008 Oxford University Press:
egoism /ˈɛgəʊɪz(ə)m, ˈiː-/

▶noun

• 1 another term for egotism.

• 2 Ethics an ethical theory that treats self-interest as the foundation of morality.

– derivatives
egoist noun,
egoistic adjective,
egoistical adjective,
egoistically adverb.