Sour grapes is the action of making something seem less important after finding out they can't have it.(noun)
An example of sour grapes is a man saying he didn't want to date a certain woman because she was dumb, after she decided to date someone else.
See sour grapes in Webster's New World College Dictionary
Origin: from Aesop's fable in which the fox, after futile efforts to reach some grapes, scorns them as being sour
See sour grapes in American Heritage Dictionary 4
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