Definition of until hell freezes over in English English dictionary
forever; One will never in their life get the results that they want, no matter what they're doing involving the situation
They can be bellyaching to me about their life's problems until hell freezes over, but it doesn't mean that they'll ever get my sympathy.
forever (relating to something that will never happen no matter what - for e.g.: "She can practice singing until hell freezes over but she will never sing in a band because she is tone-deaf")