Messenger may bother alderman a bit (6)
I believe the answer is:
herald
'messenger' is the definition.
(I know that herald is a type of messenger)
'may bother alderman a bit' is the wordplay.
'a bit' says the answer is hidden in the clue (the answer is formed by a bit of the clue).
'HERALD' is hidden within 'may bother alderman'.
(Other definitions for herald that I've seen before include "Ceremonial messenger" , "Usher in; proclaim" , "Presage for old announcer" , "College of Arms official" , "Announcer - forerunner" .)