timeless

Eternal.

When Worlds, that count his Circles now, unhing’d, (Fate the loud Signal sounding) headlong rush To timeless Night and Chaos, whence they rose.

Not affected by time; ageless.

Done at an improper time; unseasonable; untimely.

Must I behold thy timeless, cruel death?

The lamp of day is quench’d beneath the deep, And soft approach the balmy hours of sleep: Nor fits it to prolong the heav’nly feast Timeless, indecent, but retire to rest.

Not decreasing over time in quality and appeal.

The cave carvings have a timeless beauty.

Without a time limit; untimed.

a timeless cricket match

A gene encoding an essential protein that regulates circadian rhythm, normally written in italics: timeless.