RichThesaurus
until hell freezes over
vs
until the cows come home
until hell freezes over
prep
forever; without success, no matter how long one perseveres
until the cows come home
phrase
For a very long period of time.
How often have the words
until hell freezes over
and
until the cows come home
occurred in a corpus of books?
(source:
Google Ngram Viewer
)