Is his command all over? (7)
I believe the answer is:
general
'is his command 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 "Enlarge (anag.)" , "High ranking soldier" , "Common - soldier" , "Applying to all or most of a group" , "Rank; normal, usual" .)