Meaning

noun an instance of boastful talk

verb show off

adjective exceptionally good

originFrom Middle English braggen (“to make a loud noise; to speak boastfully”) of uncertain origin. Possibly related to the Middle English adjective brag (“prideful; spirited”), which is probably of Celtic origin; or from Old Norse bragr (“best; foremost; poetry”); or through Old English from Old Norse braka (“to creak”).

Etymology from Wiktionary, CC BY-SA 3.0