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."
early 13c., perfeccioun, "consummate state or form, that degree of excellence which leaves nothing to be desired," from Old French perfection "perfection, completeness" (12c.), from Latin perfectionem (nominative perfectio) "a finishing, completing, perfection," noun of action from past-participle stem of perficere "to accomplish, finish, complete" (see perfect (adj.)).
From late 14c. as "flawlessness, correctness, purity," also "act of making perfect," also "state of being complete." The meaning "quality, endowment, or acquirement characterized by excellence or great worth or value" is from 1570s.
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Harper, D. (n.d.). Etymology of self-perfection. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/self-perfection