The term 'thrash out' is a phrase used to describe a discussion or argument in which two or more people try to reach a conclusion or agreement. The crossword solutions for this term are 'ARGUE' (5 letters) and 'DEBATE' (6 letters). Both words refer to a situation in which two or more people express opposing views on a subject in order to reach a resolution. Arguing and debating involve exchanging ideas, opinions, and facts in order to come to a mutual understanding.