Lightweight or heavyweight dog? (5)
I believe the answer is:
boxer
I believe this clue is a double definition.
'lightweight or heavyweight' is the first definition.
(I know that lightweight is a type of professional boxer)
'dog?' is the second definition.
(I know that Boxer is a type of dog)
(Other definitions for boxer that I've seen before include "Pug - dog" , "Asian rebel" , "one that's accustomed to fighting" , "Tyson, perhaps - type of dog" , "Prizefighter" .)