egoism and egoist were borrowed 1785 from Fr. egoisme, egoiste, coined 1755 as philosophical terms for "thinking subject." Egotism, egotist expressing "selfishness," are native coinages from 1714, first used by Joseph Addison; the -t- is perhaps by influence of nepotism, where it belongs. Addison credits the term to "Port-Royalists" who used it in reference to obtrusive use of first person sing. pronoun in writing, hence "talking too much about oneself." Meaning "self-conceit, selfishness" is 1800. Related: Egoistic; egoistical.