'flamboyantly-displayed' is a compound built from the adverb 'flamboyantly' and the past-participle form 'displayed'. 'flamboyant' originates from French 'flamboyant' (from Old French), ultimately from Latin 'flamma' meaning 'flame'; 'display' originates from Old French 'desployer'/'despleier' meaning 'to unfold, spread out'.

'flamboyant' came into English via French 'flamboyant' (literally 'flame-like') and developed its modern figurative sense of 'showy' by the 17th–18th centuries; 'display' entered Middle English from Old French 'desployer' (Modern French 'déployer') and shifted from the literal sense 'unfold, spread' to the figurative sense 'to show' and 'to exhibit,' giving 'displayed' as the past participle used adjectivally.

Initially, 'flamboyant' meant 'flame-like' or 'flaming' and 'display' meant 'to unfold or spread out'; over time 'flamboyant' evolved to mean 'showy or ostentatious' and 'display' broadened to mean 'to exhibit' or 'to present for viewing', so together they now convey 'exhibited in a showy manner.'