Worry intervenes in attempt to find agreement (6)
I believe the answer is:
treaty
'agreement' is the definition.
(treaty is a kind of agreement)
'worry intervenes in attempt' is the wordplay.
'worry' becomes 'eat' (something worrying may eat someone up).
'intervenes' is an insertion indicator.
'in attempt' becomes 'try' (synonyms. I am not sure about the 'in' bit.).
'eat' inserted inside 'try' is 'TREATY'.
'to find' acts as a link.
Can you help me to learn more?
(Other definitions for treaty that I've seen before include "Formal agreement between two or more countries" , "International agreement" , "'Pact, accord (6)'" , "Covenant" , "Written agreement between two states" .)