Small dog, informally (4)
I believe the answer is:
peke
'small dog informally' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for peke that I've seen before include "Small dog (colloq.)" , "Small breed of dog" , "Sort of lapdog" , "Breed of dog (shortened)" , "Small canine" .)