passerby
nounUK /ˌpɑːsəˈbaɪ/
US /ˌpæsərˈbaɪ/
A person who is walking past a place.
A passerby stopped to help the lost dog.
OTHER MEANINGS
2. Someone who happens to be present when something occurs.
Several passersby saw the accident and called for help.
3. A person traveling on foot through a particular area.
The quiet street was empty except for one passerby.
4. An incidental or casual observer of an event.
To a passerby, the street festival looked like a big party.