Long-tailed rodents (4)
I believe the answer is:
rats
'long-tailed rodents' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rats that I've seen before include "Hamelin's pests" , "Mild oath - sewer residents" , "Heels" , "Oh no" , "Snoopy's imprecation - vermin" .)