These words all refer to what has no beginning or no end, or to what exists outside or beyond time. Everlasting stresses something that endures through time, particularly something that will never case to exist, once created. Eternal contrasts with this by admitting the implication that the thing described has always existed in the past, as well, and thus has neither beginning nor end.

• In Christian theology, the soul of each newborn infant is fresh creation that is immortal and consequently everlasting ; In Hinduism, the soul has no beginning and need never end and is consequently eternal .

Everlasting can also function as a negative hyperbole for a continual or constant annoyance or even for something that seems to take forever and has worn out one’s patience or tolerance; his everlasting boasting; this everlasting war. When negative, eternal is used more loosely, less specifically, and with less force: her eternal carping.

Timeless may refer more informally than eternal to something without beginning or end: the timeless laws of the universe. Even when used less literally, the word is mainly positive in its effect, referring in this case to something that does not go out of date but seems to be always fresh or relevant: the timeless poetry of Shakespeare. Timeless can also refer to something outside time or to a situation in which time seems to have stopped: It is possible to conceive of a timeless universe, but not one without space; the timeless moment of satori, or enlightenment. Unending refers more informally and exclusively than everlasting to something that has no end: the unending torment of souls condemned to hell; the philosophical view of the universe as being in an unending state of flux. Used less exactly, the word can be either an approving or disapproving hyperbole. In approval, it often suggests what is boundless as well as lasting: She gave her son unending love. In disapproval, a failure to get to the point may be implied: unending negotiations while the fighting continued.

Never-ending can point, perhaps more emphatically than unending, to what endures forever: the never-ending omniscience of God. As a loose hyperbole, the word can be positive, with a tone approaching that of timeless in this use, but with an additional suggestion of recurrent or continually renewed freshness: fairy tales that have been a never-ending delight for many generations of children. Used negatively, the word may have greater force, suggesting a tiresome refusal to come to a halt: a never-ending bore.

Endless is the most informal of these words, has the widest range of uses, and is most open to the demands of context. It can refer to something without an end in time: the endless convolutions of matter and energy. But since it can also suggest something that continues without end through space, it can be ambiguous: a theory holding that the universe was endless . As a hyperbole, it can be approving, with implications like those for unending : endless admiration; a lovely afternoon that seemed endless . More often, it is loosely used as a harsh negative: endless delays during embarkation. Interminable is the one word here that is almost exclusively limited in use as a negative hyperbole for something that is long-lasting. It is more formal then endless but is less ambiguous than the latter in referring solely to time. It is also the most harshly disapproving of these words: interminable disputations that disrupted the orderly functioning of the committee.