Is there a term of phrases where there are multiple ways to say the same meaning (that is, the phrases are synonymous), but on the surface, the structure of at least some of the phrase components have opposite meaning (that is, at least some components of each phrase are antonyms)?
For example, "fill in" and "fill out" mean the same thing (in the context of a form, e.g.). However, "in" and "out" are antonyms.
This is sort of the opposite of Auto-Antonyms. Whereas those are single words/phrases which have at least two meanings which are antonyms of each other, I'm looking for two phrases which are synonymous but are made up of pairwise antonyms.