4. The use of flaunt to mean “to ignore or treat with disdain” ( He flaunts community standards with his behavior ) is strongly objected to by many usage guides, which insist that only flout can properly express this meaning. From its earliest appearance in English in the 16th century, flaunt has had the meanings “to display oneself conspicuously, defiantly, or boldly” in public and “to parade or display ostentatiously.” These senses approach those of flout, which dates from about the same period: “to treat with disdain, scorn, or contempt; scoff at; mock.” A sentence like Once secure in his new social position, he was able to flaunt his lower-class origins can thus be ambiguous in current English. Considering the similarity in pronunciation of the two words, it is not surprising that flaunt has assumed the meanings of flout and that this use has appeared in the speech and edited writing of even well-educated, literate persons. Nevertheless, many regard the senses of flaunt and flout as entirely unrelated and concerned speakers and writers still continue to keep them separate.
1560s, "to display oneself in flashy clothes," of unknown origin; perhaps a variant of flout or vaunt. It looks French, but it corresponds to no known French word. Transitive sense is from 1827. Related: Flaunted; flaunting.