It's no rumour he's in charge (8)
I believe the answer is:
official
'it's no rumour he's in charge' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'no rumour he's in charge' is the wordplay.
I cannot quite see how this works, but
'no' could be 'o' (resembles 0 - 'no' can mean 'zero') and 'o' is found within the answer.
'in charge' could be 'ic' (abbreviation for 'in charge') and 'ic' is found within the answer.
'he' could be 'al' and 'al' is located in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for official that I've seen before include "Formally approved" , "Sanctioned by authority" , "Approved by authority" , "Publicly maintained" , "Authorative" .)