Thank you all so much. If 5d is stay up, which I thought it was, then 9a Sack Butt would start with a Y. Wondering could it be 'stop up' and then Push would fit in
I had stay rather than stop ..up . Push ?? I don't know how well that fits .
cask ....anagram of sack is another term for a butt ...but the doesn't fit in with stay up .