Exercise for us at closing time (3)
I believe the answer is:
use
'exercise' is the definition.
(I know that exercise is a kind of the use)
'us at closing time' is the wordplay.
'at' says to put letters next to each other.
'closing time' becomes 'e' (I can't justify this - if you can you should believe this answer much more).
'us'+'e'='USE'
'for' is the link.
Can you help me to learn more?
(Other definitions for use that I've seen before include "Operate" , "Exploit; custom" , "Apply, employ" , "Milk" , "Put to work" .)