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."
c. 1500, "address with a title;" 1560s, "to give a name to," from style (n.). Meaning "to arrange in (fashionable) style" (especially of hair) is attested from 1934. Slang sense of "act or play in a showy way" is by 1974, African-American vernacular. Related: Styled; styling.
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Definitions of self-styled from WordNet
as claimed by and for yourself often without justification;
the self-styled `doctor' has no degree of any kind