Green’s Dictionary of Slang

1. (US) to talk at length (and with no real importance); thus blatting n. and adj.

1884		(con. c.1840) ‘Mark Twain’ Huckleberry Finn 213: So the king he blatted along, and managed to inquire about pretty much everybody and dog in town.
1889		Thomas Co. Cat (Colby, KS) 6 June 4/1: Beware of [...] a politician who is ever blatting about his zeal for the party.
1902		Ade Forty Modern Fables 19: For a whole Evening you Blat about your own Affairs.
1913		Bemidji Dly Pioneer (MN) 7 Mar. 1/2: The New York press is continually blatting about the greatness of Wells.
1925		S. Lewis Arrowsmith 204: He’s a fine one, he is, to go around blatting that we ought to have more health precautions!
1939		Howsley Argot: Dict. of Und. Sl.
1942		P. Wylie Generation of Vipers 13: The radio blats away all day and night without the dimmest notion of responsibility for the effect of what it says.
1949		R. Chandler Little Sister 80: An evening with the sports page, the blatting of the radio.
1953		R. Chandler Long Good-Bye 107: There will be sidewalks and lamp posts and children with scooters and blatting radios.
1961		K. Vonnegut ‘Runaways’ Bagombo Snuff Box (1999) 246: The television set in the living room and the radio in the kitchen were both on, blatting away.

2. to talk wildly or loudly.

1888		C.E. Craddock Despot of Broomsedge Cove 59: Waal, ennyhows, ’t would in an’ about kill me ef he war ter go ter blatin out in the church house [...] ’bout the devil a-laffin’ at me whilst playin’ kyerds.
1909		Columbian (Bloomsburg, PA) 2 Dec. 5/2: There isn’t going to be a war, in spite of the blatting of some jingo sheets.
1913		J. London Valley of the Moon (1914) 454: He’s blattin’ around town that he can lick me with one hand tied behind ’m.
1924		C.E. Mulford Hopalong Cassidy Returns 18: You got a lot of gall blattin’ about yore two-hand rake.
1931		M. Harris ‘Facing the Mob’ in Gangland Stories Feb. 🌐 Bad News Carrie wouldn’t ‘blat’ about Smooth and her proposed revenge for a few hours.
1946		T. Heggen Mister Roberts 93: ‘Secure the special sea detail,’ was blatted over the P.A. system.
1951		S. Lewis World So Wide 235: Through these insulting port-holes she stared at Sir Henry and blatted, ‘Maybe the poor darlings of teachers haven’t enough cash to stick it out here any longer, and they got to ‘scamper’. [...] Everyone, but especially Sir Henry and perhaps Roxanna herself, seemed to consider her tone offensive.
1970		A. Young Snakes (1971) 146: The P.A. was blatting out something about Pennsylvania.
1982		S. King Running Man in Bachman Books (1995) 621: ‘I called them!’ she blatted.
2001		S. King Dreamcatcher 335: Stop that blatting, laddie-buck.

3. (US) to drive fast.

1943

R.L. Bellem ‘Half-Size Homicide’ in Speed Detective Nov. 🌐 I blatted into another right turn on Santa Monica Boulevard.