flagrant (adj.)
c.1500, "resplendent," from Latin flagrantem (nominative flagrans) "burning, blazing, glowing," figuratively "glowing with passion, eager, vehement," present participle of flagrare "to burn, blaze, glow" from Latin root *flag-, corresponding to PIE *bhleg- "to shine, flash, burn" (cognates: Greek phlegein "to burn, scorch," Latin fulgere "to shine"), from root *bhel- (1) "to shine, flash, burn" (see bleach (v.)). Sense of "glaringly offensive" first recorded 1706, probably from common legalese phrase in flagrante delicto "red-handed," literally "with the crime still blazing." Related: Flagrantly.