Nobody will deny this vague individual (7)
I believe the answer is:
someone
'nobody will deny this' is the definition.
The definition suggests a singular noun which matches the answer.
'vague individual' is the wordplay.
'vague' becomes 'some' (I can't explain this - if you can you should give a lot more credence to this answer).
'individual' becomes 'one' (an individual is one person).
'some'+'one'='SOMEONE'
Can you help me to learn more?
(Other definitions for someone that I've seen before include "Unspecified person" , "A person (maybe of importance)" , "individual" , "Important person" , "big cheese" .)