In a showy, bold, extravagant, or ostentatious manner.
Formed from 'flamboyant' with the standard adverb suffix '-ly.' This is the standard way to convert the adjective into an adverb form.
Flamboyantly is the adverb form that actually gets used regularly—while the noun forms multiply with different suffixes, this '-ly' version is the workhorse of the word family.
Complete word intelligence in one call. Free tier — 50 lookups/day.