motstukkr (OGu) noun

Literally, ‘meeting post’. Most probably one of the posts used to mark out the site of the assembly. In GL, stray cattle and ponies were to be tied up within sight of these, but a distance away, presumably so that they were not confused with animals belonging to the people attending the assembly. It is possible that the assembly was in a natural hollow and that by having the animals a distance away the men holding them could see the posts over the heads of others at the assembly, or alternatively that potential claimants could see the beasts.

assembly-site pole OGu GL A 45a Refs:

Peel 2015, 180 note 45a/10−11; Schlyter 1877, s.v. motstukker; SL GL, 286 note 2 to chapter 45a