Announced top dog (4)
I believe the answer is:
peke
'dog' is the definition.
(short for Pekingese)
'announced top' is the wordplay.
'announced' indicates a 'sounds like' (homophone) clue.
'top' becomes 'peak' (synonyms).
'peak' is a homophone of 'PEKE'.
(Other definitions for peke that I've seen before include "Sort of lapdog" , "Little dog" , "In short, it's a small short-legged dog" , "Snub-nosed lap-dog (colloq.)" , "Small canine" .)