apotropaic
Intended to ward off evil.
Wormwood [...] was associated with the rites of St. John's Eve, when a crown of the plant was made from its sprays for apotropaic purposes, to ward of malefic spirits.
Where it comes from
From Ancient Greek ἀποτρόπαιος (apotrópaios), from ἀπό (apó, “away”) and τρόπος (trópos, “turn”); thus meaning “causing things to turn away”, as in “turns away evil”.
Adapted from the Wiktionary entry apotropaic (CC BY-SA 4.0).