We found one dictionary that defines the word that ain't hay:

Miscellaneous (1 matching dictionary)

1. That ain't hay: Idioms

▸ Words similar to that ain't hay ▸ Usage examples for that ain't hay ▸ Idioms related to that ain't hay ▸ Wikipedia articles (New!) ▸ Words that often appear near that ain't hay ▸ Rhymes of that ain't hay ▸ Invented words related to that ain't hay