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.
late 14c., "to aid," also "to hold up, prop up, put up with, tolerate," from Old French suporter "to bear, endure, sustain, support" (14c.), from Latin supportare "convey, carry, bring up, bring forward," from assimilated form of sub "up from under" (see sub-) + portare "to carry," from PIE root *per- (2) "to lead, pass over." Related: Supported; supporting.
<a href="https://www.etymonline.com/word/self-supporting">Etymology of self-supporting by etymonline</a>
Harper, D. (n.d.). Etymology of self-supporting. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/self-supporting