Claim to have beer with member (6)
I believe the answer is:
allege
'claim' is the definition.
(thesaurus)
'beer with member' is the wordplay.
'beer' becomes 'ale' (I've seen this before).
'with' means one lot of letters goes inside another.
'member' becomes 'leg' (I've seen this before**).
'ale' enclosing 'leg' is 'ALLEGE'.
'to have' acts as a link.
(Other definitions for allege that I've seen before include "Aver - maintain" , "Assert, state without proof" , "Declare or accuse without proof" , "Declare without actual proof" , "Swear" .)