Green’s Dictionary of Slang

1. (US) a swinging blow.

1940

J.H. O’Hara Pal Joey 112: I could hang a blooper on it [i.e. one’s face].

2. (orig. US) an embarrassing verbal error, often delivered by a public or authority figure to their own detriment.

[1926		L.A. Times 14 Feb. B9: Warfare against bloopers is declared! With the terrific demonstration of blooping fresh in the minds of all listeners who attempted to receive foreign stations during the International Radio Week tests just concluded, the campaign announced by the Radio Digest should meet with instant success...to reduce radiation or blooping to a minimum].
1951		J. Marlow Associated Press 8 Nov. n.p.: But on one subject – ‘security’ – [Eisenhower] may have felt he pulled a political blooper.
1971		(con. 1950s) J. Brown Monkey Off My Back (1972) 101: When I reflected on that statement later I got goosebumps thinking what a blooper it had been.
1986		C. Hiaasen Tourist Season (1987) 324: A show about humorous TV bloopers came on.
1992		D. Burke Street Talk 2 85: Did you see the television program last night where they showed bloopers from the top shows?
2001		I. Rankin Falls 432: ‘Carswell’s blooper,’ Pryde said, ‘yet again.’.
2003		Mad mag. July 49: We discovered a huge blooper! In the scene where the Hulk is being blasted [etc.].