Proto-Germanic: *gruna-z; *grunōn- vb.
Meaning: suppose
Old Norse: grun-r m. `Argwohn, Vermutung, Zweifel', gruna wk. `beargwöhnen'
Norwegian: grun(e); gruna vb.
Swedish: dial. gruna `vermuten'
Old Danish: grunde `ründe ersinnen'(infl. von deutsch rund)