Picked up top dog (4)
I believe the answer is:
peke
'dog' is the definition.
(short for Pekingese)
'picked up top' is the wordplay.
'picked up' shows a homophone (sound like).
'top' becomes 'peak' (synonyms).
'peak' sounds like 'PEKE'.
(Other definitions for peke that I've seen before include "Small dog (colloq.)" , "In short, it's a small short-legged dog" , "Sort of lapdog" , "Little dog" , "Small breed of dog" .)