[Sharkû]

'fey' is an intriguing word worthy of being observed on the syntagmatic level:

Dread was round him, and enemies before him in the pass, and his master was in a fey mood running heedlessly to meet them. (Sam's experienced account in Cirith Ungol)

‘Greatly changed he [Aragorn] seemed to me since I saw him first in the king’s house,’ said Éowyn: ‘grimmer, older. Fey I thought him, and like one whom the Dead call.’ [...] Alas that a fey mood should fall on a man so greathearted in this hour of need!

But the Lord of the City [Denethor], Beregond, has fallen before his city is taken. He is fey and dangerous.’ (Pippin)

[...] Théoden could not be overtaken. Fey he seemed, or the battle-fury of his fathers ran like new tire in his veins [...]

He stood a moment as a man who is pierced in the midst of a cry by an arrow through the heart; and then his face went deathly white; and a cold fury rose in him, so that all speech failed him for a while. A fey mood took him.
‘Éowyn, Éowyn!’ he cried at last: ‘Éowyn, how come you here? What madness or devilry is this? Death, death, death! Death take us all!’ (Éomer on the Pelennor)

Then Fëanor laughed as one fey, and he cried: [...] ' ! Let the ships burn!'[...] he was fey, consumed by the flame of his own wrath.

They came upon Morwen by the banks of Sirion, and Mablung besought her to return to Menegroth; but she was fey

Then at last Túrin knew that doom had overtaken him. [...]And he laughed as one fey