adderwort means common bistort (Bistorta officinalis, syn. Persicaria bistorta) or snakeweed. Lexicurio rates it Sui generis — a strength score of 87 out of 100.
Etymology
adder + wort, as it was reputed to cure snakebite.
noun
- Common bistort (Bistorta officinalis, syn. Persicaria bistorta) or snakeweed.