[W gwair, hay].
Mysterious prisoner of Caer Siddi, another name for the otherworldly Annwfn in the pre-Norman poem Preiddiau Annwfn [The Spoils of Annwfn]. The Welsh Triads cite him as one of the three exalted prisoners of the Isle of Britain, along with Mabon. Goreu is said to have released him. Some commentators have suggested that Gwair is a title rather than a name and may refer to any of several characters in the Mabinogi, including Mabon.
See Marged Haycock, Studia Celtica, 18/19 (1983–4), 52 ff.