bræþavitni (OSw) breþa vitni (OSw) noun

Probably a witness — a person or a testimony — of a crime done in public with eyewitnesses, that was to be called upon immediately in connection with the deed. In YVgL, the scene of the crime was the assembly itself, but in UL these witnesses could be used whenever a killer, attacker or thief was caught in the act.

quick witness OSw YVgL Urb
witness of a sudden act OSw UL Rb Refs:

Schlyter s.v. bræþa vitni