To struggle to decide or determine something: advisers thrashing about trying to develop a new policy. To discuss fully or produce by discussion: thrashed out their differences; thrashed out an agreement. [Variant of thresh.]

What is the meaning of thrashed out?

: to talk about (something) in order to make a decision, find a solution, etc. They had a meeting to thrash out their problems.

What does hammered out mean?

transitive verb. : to produce or bring about as if by repeated blows hammered out an agreement.