Magistrate and everything he left here is less substantial (7)
I believe the answer is:
smaller
'substantial' is the definition.
Both the answer and definition are adjectives. Maybe they are linked in a way I don't understand?
'magistrate and everything he left here is less' is the wordplay.
I cannot really see how this works, but
'everything' could be 'all' (all things) and 'all' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for smaller that I've seen before include "More diminutive" , "Less extensive" , "Not as big as" , "Sell ram (anag.)" .)