late 14c., "flame-like in appearance;" c. 1400, "on fire," present-participle adjective from flame (v.). Meaning "of bright or gaudy colors" is from mid-15c. As an intensifying adjective, late 19c. Meaning "glaringly homosexual" is homosexual slang, 1970s (along with flamer (n.) "conspicuously homosexual man"); but flamer "glaringly conspicuous person or thing" (1809) and flaming "glaringly conspicuous" (1781) are much earlier in a general sense, both originally with reference to "wenches." Related: Flamingly.

"on fire, ablaze," 1550s, from a- (1) "on" + flame (n.). Figurative use by 1856.

1590s, agent noun from flame (v.). Figurative sense "glaringly conspicuous person" is from 1809. For homosexual slang sense, see flaming.

also flamethrower, 1917, translating German Flammenwerfer (1915). See flame (n.) + throw (v.).

long-legged, long-necked brightly colored pink bird of the tropical Americas, 1560s, from Portuguese flamengo, Spanish flamengo, literally "flame-colored" (compare Greek phoinikopteros "flamingo," literally "red-feathered"), from Provençal flamenc, from flama "flame" (see flame (n.)) + Germanic suffix -enc "-ing, belonging to." Perhaps accommodated to words for Fleming (see flamenco).

1813, from stem of Latin flammare "to set on fire" (from flamma "flame, blazing fire;" see flame (n.)) + -able. In modern (20c.) use, a way to distinguish from the ambiguity of inflammable.

mid-14c., "make (someone) ardent; set (the spirit, etc.) on fire" with a passion or religious virtue, a figurative sense, from Old French enflamer "catch fire; set on fire" (Modern French enflammer), from Latin inflammare "to set on fire, kindle," figuratively "to rouse, excite," from in- "in" (from PIE root *en "in") + flammare "to flame," from flamma "a flame" (see flame (n.)).

The literal sense of "to cause to burn" first recorded in English late 14c. Meaning "to heat, make hot, cause inflammation" is from 1520s. Formerly also enflame, but since 16c. the spelling with in- has predominated. Related: Inflamed; Inflaming.

Proto-Indo-European root meaning "to shine, flash, burn," also "shining white" and forming words for bright colors.

It might form all or part of: beluga; Beltane; black; blancmange; blanch; blank; blanket; blaze (n.1) "bright flame, fire;" bleach; bleak; blemish; blench; blende; blend; blind; blindfold; blitzkrieg; blond; blue (adj.1); blush; conflagration; deflagration; effulgence; effulgent; flagrant; flambe; flambeau; flamboyant; flame; flamingo; flammable; Flavian; Flavius; fulgent; fulminate; inflame; inflammable; phlegm; phlegmatic; phlogiston; phlox; purblind; refulgent; riboflavin.

It might also be the source of: Sanskrit bhrajate "shines;" Greek phlegein "to burn;" Latin flamma "flame," fulmen "lightning," fulgere "to shine, flash," flagrare "to burn, blaze, glow;" Old Church Slavonic belu "white;" Lithuanian balnas "pale."