Turning something over quickly with a quick movement, or in British slang, used as a mild curse word to emphasize annoyance.
From 'flip' which originated in the 1500s as imitative of the sound/motion. British slang use as an intensifier emerged in the mid-20th century as a euphemism.
The word 'flipping' became a clever British way to sound frustrated without being rude—you could say 'flipping heck!' in front of teachers and adults without actually swearing!
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