sour grapes

Fig. something that one cannot have and so disparages as if it were never desirable. of course you want to buy this expensive jacket. Criticizing it is just sour grapes, but you still really want it.

if you say that something someone says is sour grapes, you mean that they said it because they are jealous I don't think it's such a great job - and that's not just sour grapes because I didn't get it.

Disparaging what one cannot obtain, as in The losers' scorn for the award is pure sour grapes. This expression alludes to the Greek writer Aesop's famous fable about a fox that cannot reach some grapes on a high vine and announces that they are sour. In English the fable was first recorded in William Caxton's 1484 translation, "The fox said these raisins be sour."