"a portrait of oneself, by oneself," 1821, from self- + portrait, translating German Selbstbildnis.
Entries linking to self-portrait
self-
word forming element indicating "oneself," also "automatic," from Old English use of self (pron.) in compounds, such as selfbana "suicide," selflice "self-love, pride, vanity, egotism," selfwill "free will." Middle English had self-witte "one's own knowledge and intelligence" (early 15c.).
OED counts 13 such compounds in Old English. Middle English Compendium lists four, counting the self-will group as a whole. It re-emerges as a living word-forming element mid-16c., "probably to a great extent by imitation or reminiscence of Greek compounds in (auto-)," and formed a great many words in the pamphlet disputes of the 17c.
portrait n.
1560s, "a figure, drawn or painted," a back formation from portraiture or directly from French portrait, from Old French portret (13c.), noun use of past participle of portraire "to paint, depict" (see portray). Especially a picture or representation of the head and face of a person drawn from life. Related: Portraitist.