Claret blending combine? (6)
I believe the answer is:
cartel
'combine?' is the definition.
(I know that combine can be written as cartel)
'claret blending' is the wordplay.
'blending' indicates anagramming the letters (letters blended or mixed into a new form).
'claret' is an anagram of 'CARTEL'.
(Other definitions for cartel that I've seen before include "Group formed to limit competition" , "Business combine to restrict competition" , "Business monopoly for claret" , "Group of firms that agree fixed prices in order to limit competition" , "Syndicate formed to restrict competition" .)