Pestered by stocky burrowing mammal? (8)
I believe the answer is:
badgered
'pestered' is the definition.
('badger' can be a synonym of 'pester')
'by stocky burrowing mammal?' is the wordplay.
'by' means one lot of letters go next to another.
'stocky' becomes 'ed' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'burrowing mammal?' becomes 'badger' (I've seen this before).
'ed' put after 'badger' is 'BADGERED'.
Can you help me to learn more?
(Other definitions for badgered that I've seen before include "Pestered" , "chivvied" , "Annoyed persistently" , "hassled" , "Harassed" .)