Very short tailless mini rodents? (6)
I believe the answer is:
vermin
'rodents?' is the definition.
(rodents may be considered vermin)
'very short tailless mini' is the wordplay.
'short' means to remove the last letter.
'tailless' means to remove the last letter (the tail of the word is removed).
'very' with its last letter taken off is 'ver'.
'mini' with its last letter removed is 'min'.
'ver'+'min'='VERMIN'
(Other definitions for vermin that I've seen before include "Rodents that spread disease" , "E.g. unpleasant rodents" , "Harmful or disease-ridden animals" , "Common animals and birds, like rats and crows" , "Dirty rats?" .)