know someone by sight

Meaning

This expression means to recognize someone's face or appearance without actually knowing their name or having a personal relationship with them. It is commonly used when talking about neighbors, colleagues from other departments, or people you see regularly on your daily commute. The tone is completely neutral and objective.

Examples

• I don't know the new neighbor's name, but I know him by sight.

  I don't know the new neighbor's name, but I know him by sight.

• We've never actually spoken, but we know each other by sight from the gym.

  We've never actually spoken, but we know each other by sight from the gym.

• She works in the same building, so I only know her by sight.

  She works in the same building, so I only know her by sight.

• Do you know the barista at the corner cafe? Only by sight, really.

  Do you know the barista at the corner cafe? Only by sight, really.

• I know most of my classmates by sight, but I haven't talked to all of them yet.

  I know most of my classmates by sight, but I haven't talked to all of them yet.

Common Mistakes

• ✗ I know him by face.

  ✓ I know him by sight.

  Learners often translate literally from their native language using 'by face' or 'from face.' The natural English idiom is 'by sight.'

• ✗ I know her by sightly.

  ✓ I know her by sight.

  'Singly' or 'sightly' are incorrect. The noun 'sight' must be used in this fixed prepositional phrase.

Related Expressions

Practice

• I see that postman every day, so I ___ by sight, but I don't know his name.

  💡 Use the verb 'know' followed by the object pronoun.

  Show answer

  know him

• Do you actually know Sarah, or do you just know her ___?

  💡 The phrase for recognizing someone's appearance without knowing them personally.

  Show answer

  by sight