Socialise or talk informally (6)
I believe the answer is:
hobnob
This clue is a double definition.
'socialise' is the first definition.
(I've seen this before)
'talk informally' is the second definition.
(I've seen this before)
(Other definitions for hobnob that I've seen before include "Hang out with people of standing" , "Spend time chatting to a VIP?" , "familiar talk" , "Fraternise, mingle" , "Associate familiarly" .)