Scrounger in pub purchasing 'substantial meal' (6)
I believe the answer is:
beggar
'scrounger' is the definition.
(thesaurus)
'pub purchasing substantial meal' is the wordplay.
'pub' becomes 'bar' (both are drinking establishments).
'purchasing' means one lot of letters goes inside another (some letters take possession of others).
'substantial meal' becomes 'egg' (I can't justify this - if you can you should give a lot more credence to this answer).
'bar' enclosing 'egg' is 'BEGGAR'.
'in' is the link.
Can you help me to learn more?
(Other definitions for beggar that I've seen before include "One seeking alms" , "Mendicant or scrounger" , "One importuning" , "I need bread" , "Poor person; outshine" .)