No ministry man is unimportant (7)
I believe the answer is:
nominal
'unimportant' is the definition.
Both the definition and answer are adjectives. Perhaps they are linked in a way I don't understand?
'no ministry man' is the wordplay.
'ministry' becomes 'min' (I can't justify this - if you can you should believe this answer much more).
'man' becomes 'Al' (man's name).
'no'+'min'+'al'='NOMINAL'
'is' is the link.
Can you help me to learn more?
(Other definitions for nominal that I've seen before include "So-called, but not in reality" , "In name only or of token value (7)" , "unreal" , "In name only, like face value of coin" , "Ostensible" .)