What does blooper mean?

blooper meaning in Etymology Dictionary

"blunder," 1943, evidently first-in theater, from United states English baseball slang indicating "a fly baseball in increased arc missed because of the fielder" (1937) or otherwise from earlier sense "radio receiver that disturbs nearby sets" when a careless operator throws it into oscillation (1926), in which particular case it imitates the ensuing sound.

blooper meaning in General Dictionary

an uncomfortable mistake