Small mammal (6)
(Other definitions for rabbit that I've seen before include "Bunny; chatter idly" , "Poor player" , "See 17" , "Fur; chatter (colloq.)" , "Waffle" .)
'small mammal' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for weasel that I've seen before include "Sly type" , "Sneaky person - small, long-necked carnivorous animal" , "Mammal related to stoat" , "Small fierce animal with slender body and reddish-brown fur" , "Small carnivore" .)
(Other definitions for vole that I've seen before include "Love this rodent, strangely" , "Small mammal - one to love" , "Holm-oak" , "River bank rodent" , "creature" .)
(Other definitions for hare that I've seen before include "Herbivore" , "Rabbit-like animal" , "Leveret" , "'First catch your ....; then cook it'" , "Mammal - run fast" .)