Short, sturdy (6)
I believe the answer is:
stocky
I believe this clue is a double definition.
'short' is the first definition.
(similar in meaning)
'sturdy' is the second definition.
(thesaurus)
(Other definitions for stocky that I've seen before include "Heavily-built" , "Thickset" , "Broad" , "Short and solidly built" , "Small and well built" .)