When celebrities get married in Korea, as an expression of jealousy, we sometimes say "He became an off-the-market man". I heard "He's off the market" is slang to mean "someone is not in the marriage market any more", but is "off-the-maket man" also possible?
ex)He's off the market
He's an off-the-maket man.
I don't think I've met it as a predicative adjective [Is that the word? Formal grammar isn't my Thing. I mean a one-word (with hyphens if it's more than one, as in 'one-word') adjective coming before the noun it describes.] But I wouldn't be surprised if I heard it used attributively:'He's off the market'.
b
So just to be clear "He's off the market" is common enough. It's the adjective form we are saying we are unfamiliar with.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.