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THE IDIOM COLLECTION LEARN & PRACTISE

Go off the rails

Understand the meaning. See it in context. Make it yours.

01 / UNDERSTAND

Meaning in plain English

Start behaving in an unacceptable or seriously irresponsible way.

02 / SEE IT IN CONTEXT

The expression in a sentence

  1. In the film, the trusted accountant goes off the rails and steals from the firm.

03 / CHECK YOUR UNDERSTANDING

Quick idiom quiz

Try the question without looking back, then write a sentence of your own. You can retry as often as you like.

Can you recall the expression?

Which expression from this lesson matches this meaning?

Start behaving in an unacceptable or seriously irresponsible way.
Show the answer

Go off the rails — Start behaving in an unacceptable or seriously irresponsible way.

Try your own sentence (optional)

Make it yours

Write one sentence using “Go off the rails” about your own life.

Check your sentence

Does your sentence match this meaning?

Start behaving in an unacceptable or seriously irresponsible way.

Compare: In the film, the trusted accountant goes off the rails and steals from the firm.

Check the spelling and how the expression fits the sentence. Your example can be different.

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GO DEEPER

More ways to understand and use it

When to use it

Use this informal expression about a significant deterioration in someone’s behaviour. It sounds critical and should not be used merely because someone makes an unusual choice.

More examples in context

  • The character went off the rails after joining a dishonest business partner.
  • Her brother worried that she was going off the rails when she began cheating customers.

Usage note

The past tense is “went off the rails”. This lesson focuses on behaviour, particularly dishonest or irresponsible conduct; ordinary disagreement alone does not fit the meaning.

A short conversation

A: Why does the detective start investigating his old friend?
B: He thinks his friend has gone off the rails and joined the smugglers.
A: That makes the story more complicated.

One more practice question

Which fictional character has gone off the rails?

A. A reliable employee who begins stealing and lying.
B. An employee who politely suggests a different schedule.

Check your answer

A. The first character’s behaviour has become seriously unacceptable.

Related lessons

Meaning and usage checked against Cambridge Dictionary. Explanations, examples and conversation are original.

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