sempiternal

As an adjective sempiternal

is seemingly everlasting or eternal.

As a noun null is

zero, nil; the cardinal number before einn.

As a letter s

is the letter s with a.

As an adjective sempiternal is

seemingly everlasting or eternal.

As adjectives the difference between sempiternal and deathless

is that sempiternal is seemingly everlasting or eternal while deathless is undying or immortal.

As adjectives the difference between sempiternal and endless

is that sempiternal is seemingly everlasting or eternal while endless is having no end.

As adjectives the difference between ephemeral and sempiternal

is that ephemeral is lasting for a short period of time while sempiternal is seemingly everlasting or eternal.

As a noun ephemeral

is something which lasts for a short period of time.

As adjectives the difference between immortal and sempiternal

is that immortal is not susceptible to death; living forever; never dying while sempiternal is seemingly everlasting or eternal.

As a noun immortal

is one who is not susceptible to death.

As a noun infinite

is infinity, endlessness.

As an adjective sempiternal is

seemingly everlasting or eternal.

As adjectives the difference between permanent and sempiternal

is that permanent is without end, eternal while sempiternal is seemingly everlasting or eternal.

As a noun permanent

is a chemical hair treatment imparting or removing curliness, whose effects typically last for a period of weeks; a perm.

As a verb permanent

is (dated) to perm (the hair).

As adjectives the difference between sempiternal and undefined

is that sempiternal is seemingly everlasting or eternal while undefined is lacking a definition or value.