Pants, just no top (5)
I believe the answer is:
awful
'pants' is the definition.
(I've seen this before)
'just no top' is the wordplay.
'just' becomes 'lawful' (showing justice).
'no top' means to remove the first letter.
'lawful' with its initial letter removed is 'AWFUL'.
(Other definitions for awful that I've seen before include "Dreadful, nasty" , "Not good at all" , "Dreadful, really bad" , "Dreadful - spine-chilling" , "Disgusting" .)