vburt
Probably a misprint for vvurt; that is, wurt. If so, then it is the past subjunctive from Proto-Germanic *werรพanฤ . Compare Gothic ๐ ๐ฐ๐ฟ๐๐ธ๐น โ(waurรพi) (from ๐ ๐ฐ๐น๐๐ธ๐ฐ๐ฝ โ(wairรพan)).