go behind someone's back

Meaning

This expression means to do something secretly or without someone's knowledge, especially when they have a right to know. It usually implies a betrayal of trust or a lack of respect for the other person's feelings or authority. The tone is often accusatory or disappointed.

Examples

• I can't believe you went behind my back and told Sarah about our plans.

  I can't believe you went behind my back and told Sarah about our plans.

• She felt betrayed when her co-worker went behind her back to the manager.

  She felt betrayed when her co-worker went behind her back to the manager.

• Instead of going behind his back, you should just talk to him directly about the issue.

  Instead of going behind his back, you should just talk to him directly about the issue.

• They decided to buy the house, going behind their agent's back to negotiate with the owner.

  They decided to buy the house, going behind their agent's back to negotiate with the owner.

• He promised he wouldn't go behind my back again, but I find it hard to trust him.

  He promised he wouldn't go behind my back again, but I find it hard to trust him.

Common Mistakes

• ✗ He went behind my back side to talk to my boss.

  ✓ He went behind my back to talk to my boss.

  The idiom is strictly 'behind someone's back'. Adding 'side' makes it literal and incorrect.

• ✗ She went behind back of me.

  ✓ She went behind my back.

  Use a possessive pronoun (my, his, her, their) before 'back' rather than 'behind back of [person]'.

Related Expressions

Practice

• I thought we were partners, but you went ___ and signed the contract without me.

  💡 secretly did something without my permission

  Show answer

  behind my back

• If you have a problem with my work, tell me directly instead of going ___.

  💡 acting secretly to avoid direct confrontation

  Show answer

  behind my back