Colony of rabbits (6)
I believe the answer is:
warren
'colony of rabbits' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for warren that I've seen before include "Area of rabbit burrows" , "densely populated area" , "In Hastings, for example," , "Network of caves as built by rabbits" , "Maze of passages" .)