This is not a duplicate of ["anymore" vs. "any more"][1].  I made sure.  In that case, the two terms being compared were noun phrase (any more) vs. adverb (anymore).  In this case, the two are both noun terms.  I know which is more often used, but is "any thing" incorrect?

The question was raised in my mind when I saw "any thing" on a post, and wondered whether to edit it to "anything".

  [1]: https://english.stackexchange.com/questions/31167/anymore-vs-any-more