Is his military career all over? (7)
I believe the answer is:
general
'is his military career all over?' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
This is the entire clue.
Can you help me to learn more?
(Other definitions for general that I've seen before include "blanket" , "Enlarge (anag.)" , "Army rank" , "Military commander" , "Popular" .)