Meanings
- idiomaticinformalSynonym of that'll be the day (“said in reply to something that one believes will never happen”).
Synonyms: that'll be the day
Synonyms & antonyms
phraseSynonym of that'll be the day (“said in reply to something that one believes will never happen”).
Origin
Probably a humorous elaboration of that’ll be the day, with frosty and Friday chosen for the alliteration; probably also implicitly evoking a cold day in Hell, referring to when Hell freezes over.
Full word history & related roots →Rhymes & wordplay
Rhymes with that'll be the frosty Friday
All rhymes →Cite this entry
that'll be the frosty Friday. (n.d.). In WatkinsX Dictionary. Retrieved November 5, 2026, from https://dictionary.watkinsx.com/word/that'll%20be%20the%20frosty%20Friday
“that'll be the frosty Friday.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/that'll%20be%20the%20frosty%20Friday. Accessed November 5, 2026.
WatkinsX Dictionary, s.v. “that'll be the frosty Friday,” accessed November 5, 2026, https://dictionary.watkinsx.com/word/that'll%20be%20the%20frosty%20Friday.
Source: that'll be the frosty Friday on Wiktionary, CC BY-SA 4.0.