to brag; to boast; to blabber; to tattle; to talk big/through one's hat; to shoot off one's mouth; to be garrulous/talkative/telltale
he always brags that he has been a globe-trotter
she boasts that she has never missed a day's work because of illness
what's the old fortune-teller blabbering about?
to blab out secrets
to jabber, to talk a lot of nonsense
braggart, boaster, blabbermouth, windbag, chatterbox
to become garrulous after a few glasses of beer