A person who sees an event, typically a crime or accident, take place

A person who is present at an event

उपस्थित व्यक्ति

English Usage: She was a witnesser at the historic event held last week.

Hindi Usage: वह पिछले हफ्ते आयोजित ऐतिहासिक कार्यक्रम में उपस्थित व्यक्ति थी।