passerby

passerby — noun

1. someone who is going past a place, often by chance and without being part of wha

1.nounB2
Definition

someone who is going past a place, often by chance and without being part of what is happening there.

Example

Marcus asked a passerby where the nearest post office was.

ask a passerby where ...

A passerby heard the crash and called an ambulance from the corner shop.

passerby as chance witness

Common collocations
  • ask a passerby
  • stop a passerby
  • curious passerby
  • random passerby
  • group of passersby
Synonyms
  • bystander

    often used when someone is near an accident, fight, or other unexpected event

  • onlooker

    suggests stopping to watch with interest or curiosity

  • pedestrian

    broader and more technical; simply means a person walking

  • witness

    used when the person saw something important and can report it later

Grammar Patterns

a passerby

[number] passersby

ask a passerby for [information]

Usage Note

Usually refers to someone unknown who is only at the scene for a short time, not a person who belongs there. The irregular plural is 'passersby', and the word is especially common in reports about accidents or street events.

Common Mistakes

Several passerby stopped to help the cyclist.
Several passersby stopped to help the cyclist.
the plural adds -s to 'passer', not to 'by'.
The shop owner chatted with the same passerby every morning.
The shop owner chatted with the same neighbour every morning.
a passerby is someone only going past, not a regular local person.

Word family

Synonym discussion

Sense: noun/1

These words can all describe someone near an event, but they focus on different roles. A passerby is simply a person going past a place, usually by chance and only for a moment. A bystander is nearby too, but the word often stresses not taking action, especially in an accident or argument. An onlooker suggests someone who stops to watch with interest. A pedestrian is broader and more neutral: it just means a person walking on a road or pavement. A witness matters when the person saw something important and can later describe it to police or in court. A woman hurrying past a shop is a passerby or pedestrian; after she sees a robbery and gives a statement, she becomes a witness.

passerby ↗bystanderonlookerpedestrian ↗witness ↗

Common collocations

Nouns

  • curious passerby
  • random passerby
  • group of passersby
  • fellow passerby

Phrases

  • ask a passerby
  • stop a passerby
  • a passerby saw
  • passersby gathered

Etymology

English

Formed in English from the verb phrase 'pass by' plus the ending '-er', meaning 'a person who goes past'. Because the main noun idea sits in 'passer', the plural became 'passersby' rather than 'passerbys'. The word is part of a small English pattern where the middle element takes the plural ending, like 'brothers-in-law' and 'runners-up'.