Have a meal in attempt to get agreement (6)
I believe the answer is:
treaty
'agreement' is the definition.
(treaty is a kind of agreement)
'have a meal in attempt' is the wordplay.
'have a meal' becomes 'eat' (I've seen this before).
'in' means one lot of letters goes inside another.
'attempt' becomes 'try' (I've seen this before).
'eat' put into 'try' is 'TREATY'.
'to get' is the link.
(Other definitions for treaty that I've seen before include "Formal agreement between nations" , "Compact; concordat" , "Formal agreement between two or more countries" , "Negotiation" , "Pact, accord between states" .)