adj. unending, ceaseless, eternal, everlasting; limitless
adv. ceaselessly, everlastingly, eternally; without limit
n. ceaselessness; limitlessness
v. to eternalize, immortalize, make everlasting; to make limitless

Zu'u unslaad! Zu'u nis oblaan!
I am eternal! I cannot end! (be ended/be killed)
(Alduin, 000ED359)

Ponder the meaning of spirit. Unslaad zii. Where mortal flesh may wither and die, the spirit endures.
(Paarthurnax, 000E8274)

The Nords of those days used the Dragonrend Shout to cripple Alduin. But this was not enough. Ok mulaag unslaad.
Ok mulaag unslaad = “his strength (is) unending”
(Dialogue File, 0003FA46)

Het nok Faal Vahlok, deinmaar do Dovahgolz ahrk aan Fus do unslaad rahgol ahrk vulom.
Here lies The Guardian, keeper of the Dragonstone and a Force of eternal rage and darkness.
(Word Wall for Fus, Unrelenting Force)

Het ont kriist Miraak, wo ahtiid ok sahvot ol Qah, spaan naal Deyra fah ok unslaad midun.
Here once stood Miraak, who wore his faith as Armor, shielded by the Daedra for his unending loyalty.
(Word Wall for Qah, Dragon Aspect)

Without end or limit. Much more common than synonym unahzaal ‘unending’.

Possibly from laat ‘last’’. Likely shares negative prefix un- with unahzaal ‘unending’

The phrase evgir unslaad ‘season unending’ is an ancient Nordic phrase for war.