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.
1620s, "to pray against or for deliverance from, pray the removal or deliverance from," from Latin deprecatus, past participle of deprecari "to pray (something) away," from de "away" (see de-) + precari "to pray" (from PIE root *prek- "to ask, entreat"). Meaning "to express disapproval, urge against" is from 1640s. Related: Deprecated, deprecating.
<a href="https://www.etymonline.com/word/self-deprecating">Etymology of self-deprecating by etymonline</a>
Harper, D. (n.d.). Etymology of self-deprecating. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/self-deprecating