"justification of oneself," 1650s, from self- + justification.
Entries linking to self-justification
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.
justification n.
late 14c., "administration of justice," from Late Latin iustificationem (nominative iustificatio), noun of action from past-participle stem of iustificare "act justly toward; make just" (see justify). Meaning "action of justifying, showing something to be just or right" is from late 15c. Theological sense "act by which the soul is reconciled to God" is from 1520s. Meaning "act of adjusting or making exact" in typography is from 1670s.