An Etymological Dictionary of the German Language/herb

by Friedrich Kluge

herb, adj., from the equiv. MidHG. hęre, inflected hęrwer (also hare, inflected harwer), ‘bitter, harsh’; Goth. and OHG. *har-wa- is wanting. Allied to OSax. har-m, AS. hear-m, adj., ‘painful, mortifying, bitter’?. See Harm.