thrash out

discuss something fully and in detail until you reach an agreement

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What does "thrash sth out" mean?

To thrash something out is to engage in an intensive, often contentious discussion with one or more people until a solution, agreement, or plan is reached. The process is never quick or comfortable — it implies real disagreement, complexity, and sustained effort before any resolution emerges. The metaphor draws on the physical sense of thrashing, conveying the forcefulness of the exchange. You will most often encounter this phrasal verb in political reporting, business journalism, and formal negotiation contexts, typically with objects like a deal, an agreement, the terms, or a compromise. It is more characteristic of British English than American English, where 'hammer out' tends to serve the same purpose.

Examples

How to use it

thrash out + agreement/deal/terms

The most common pattern, used when the object is a noun phrase referring to an agreement, plan, or set of terms.

After three days of intense talks, the parties finally thrashed out a settlement that both sides could accept.

thrash + object + out

Separation is natural and common with short noun phrases, particularly to give emphasis to the object.

The committee spent the entire afternoon thrashing the budget details out before the deadline.

thrash it/them out

Pronouns must always go between the verb and the particle; 'thrash it out' is especially idiomatic, even when 'it' refers only vaguely to the matter at hand.

There were real disagreements on both sides, so they agreed to meet early the next morning and thrash it out.

be thrashed out

The passive is natural, particularly in formal or journalistic writing where the focus is on the agreement rather than the negotiators.

The final terms of the contract were thrashed out over the course of several difficult meetings.

need to / try to / meet to + thrash out

The infinitive form is frequently used after verbs expressing purpose or necessity, especially in business and political contexts.

Senior officials from both governments will meet next week to thrash out the terms of the proposed trade framework.

Common Collocations

a dealan agreementthe detailsthe termsa compromisea solution

Common Mistakes

Confusing 'thrash out' with 'iron out'

'Thrash out' describes a major, intensive negotiation of significant issues from scratch, whereas 'iron out' is used for resolving smaller, remaining problems or minor differences. Using 'iron out' for a full-scale negotiation understates the difficulty involved.

✗ The diplomats spent weeks ironing out a peace agreement.
✓ The diplomats spent weeks thrashing out a peace agreement.
Using it for quick or easy discussions

'Thrash out' inherently implies effort, length, and difficulty — using it for a quick or routine conversation contradicts the word's meaning and will sound unnatural to native speakers.

✗ We thrashed out the lunch order in about two minutes.
✓ We thrashed out the terms of the merger after weeks of difficult negotiations.
Pronoun placed after the particle

When using a pronoun as the object, it must always go between 'thrash' and 'out', never after 'out'.

✗ They eventually thrashed out it after several rounds of talks.
✓ They eventually thrashed it out after several rounds of talks.

Usage

This phrasal verb is more common in British English than American English, and belongs to formal/journalistic language. It almost always suggests a difficult, lengthy discussion, not a quick or easy conversation.

Frequently Asked Questions

Is 'thrash out' British English? Would an American say something different?

Yes, 'thrash out' is predominantly British English and is especially common in British journalism and formal speech. American English speakers tend to prefer 'hammer out' in equivalent contexts — for example, 'they hammered out a deal'. Both convey the same idea of reaching an agreement through hard negotiation.

Can 'thrash out' be used for any kind of discussion, or only negotiations?

It is almost always used for high-stakes discussions involving disagreement, complexity, or competing interests — such as business deals, diplomatic agreements, policy decisions, or contractual terms. It would sound odd applied to casual or abstract conversations. The discussion must have a concrete goal, such as an agreement, plan, or solution.

Can I say 'they thrash out agreements every week' to describe a habitual action?

This sounds quite unnatural. 'Thrash out' works best in the past, present perfect, present continuous, or in infinitive constructions. Using it in the habitual present simple sits awkwardly with the sense of prolonged effort that the phrase implies — if something happens every week, it no longer feels like the hard-won struggle the verb suggests.

Does 'thrash out' always have to refer to something specific, or can I use it vaguely?

'Thrash it out' is particularly common as a vague or quasi-intransitive expression, where 'it' refers loosely to whatever difficult matter is at hand. Saying 'we need to sit down and thrash it out' without specifying what 'it' is feels entirely natural in context, and is a very idiomatic use of the phrase.

Is there a difference between 'thrash out a deal' and 'a deal was thrashed out'?

Both are correct and natural, but the passive version shifts focus onto the outcome — the deal — rather than the people who negotiated it. The passive form is particularly common in journalism and formal writing, where the result of the negotiation matters more than identifying who was responsible for reaching it.

Related Phrasal Verbs

hash sth out
hammer sb/sth out

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