Green’s Dictionary of Slang

1. anything considered very enjoyable, superlative, first-rate.

1941		D. Burley N.Y. Amsterdam Star-News 21 June 13: He spieled [...] some jive thta was a solid gasser.
1942		W. Winchell On Broadway 31 Mar. [synd. col.] Yo is convinced Florida is a gasser from Alcatrasser.
1958		Kerouac letter 19 June in Charters II (1999) 134: I just sold them a story about, a travel article I mean, called ‘Tangiers to London,’ a gasser.
1960		Mad mag. Jan. 49: Pops! he was a gasser!
1961		Mad mag. Dec. 49: I dig this White House pad / It’s just a gasser, dad.
1969		N. Cohn Awopbop. (1970) 92: Murray the K’s Golden Gassers.
1975		L. Rosten Dear ‘Herm’ 14: My wife Flo says only a ‘pro’ author could come up with a gasser like that!
1986		S. King It (1987) 755: SHOPLIFTING IS NOT A ‘KICK’ OR A ‘GROOVE’ OR A ‘GASSER!’.

2. a man or woman highly admired, considered to be the best.

1944		Cab Calloway New Hepsters Dict. in Calloway (1976) 255: gasser (n., adj.): sensational. ex., ‘when it comes to dancing, she’s a gasser’.
1958		Hughes & Bontemps Book of Negro Folklore 483: gasser : An exciting thing. Eartha Kitt is a gasser.
1961		Rigney & Smith Real Bohemia 51: Spade [Negro] guy I know is a gasser – a beautiful person.
1965		Wisconsin State Jrnl 17 Jan. 1-2: The coeds might describe the handsome guy as a ‘mass gasser,’ or a guy ‘who turns me on.’.

3. a friend.

1961

R.A. Norton Through Beatnik Eyeballs 13: Got me a couple of gassers which really enliven me, and mostly we just defy what we don’t dig.