Bulky, heavy (5)
I believe the answer is:
hefty
This clue is a double definition.
'bulky' is the first definition.
(thesaurus)
'heavy' is the second definition.
(similar in meaning)
(Other definitions for hefty that I've seen before include "Sizeable" , "With weight" , "Big and strong" , "Large and beefy" , "Hulking" .)