Team up because cask-maker had a meal (9)
I believe the answer is:
cooperate
'team up' is the definition.
(thesaurus)
'cask-maker had a meal' is the wordplay.
'cask maker' becomes 'cooper' (I've seen this in another clue).
'had a meal' becomes 'ate' (ate a meal).
'cooper'+'ate'='COOPERATE'
'because' is the link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for cooperate that I've seen before include "Work constructively with others" , "Work to the same end" , "Work with another, be helpful" , "Work together on a common enterprise" , "fit in with others" .)