One advising section of Government organisation (6)
I believe the answer is:
mentor
'one advising section' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'of government organisation' is the wordplay.
'of' indicates the answer is hidden within the clue.
'MENTOR' is hidden in the letters of 'government organisation'.
Can you help me to learn more?
(Other definitions for mentor that I've seen before include "A trusted adviser or teacher" , "Wise counsellor (of protege)" , "A trusted advisor or teacher" , "One guiding" , "Wise and trusted adviser" .)