Relatives a little less than kind (3)
I believe the answer is:
kin
'relatives' is the definition.
(I've seen this before)
'a little less than kind' is the wordplay.
'a little less than' means to remove the last letter (most but not all of the word).
'kind' with its last letter removed is 'KIN'.
(Other definitions for kin that I've seen before include "Family members" , "A person's relatives, goes with kith" , "Relations, go with kith" , "Relatives, family" , "Relatives from Kinnegad" .)