Noblewoman in pub with one's son (8)
I believe the answer is:
baroness
'noblewoman' is the definition.
(baroness is a kind of noblewoman)
'pub with one's son' is the wordplay.
'pub' becomes 'bar' (both are drinking establishments).
'with' means one lot of letters go next to another.
'son' becomes 's' (genealogical abbreviation for son).
'bar'+'ones'+'s'='BARONESS'
'in' is the link.
(Other definitions for baroness that I've seen before include "Aristocrat" , "Noblewoman" , "Thatcher possibly" , "Lady peer" , "Woman life-peer" .)