Cyhyraeth

Unclear etymology, thought to mean "death; wraith". The first element could be from the noun cyhyr "muscle, tendon; flesh", or from cyoer, from oer "cold", with the last element being the noun aeth meaning "pain", "woe", "grief", "fear." It could also simply be the suffix -aeth (roughly equivalent to English -ness or -ity).

In Welsh mythology, the Cyhyraeth (also known as the Hag of the Mist, or the Gwrach-y-Rhibyn) is a ghostly spirit (comparable with the Irish Banshee) in Welsh folklore.