endless

As an adjective endless

is having no end.

As a noun eternity is

(uncountable) existence without end, infinite time.

As adjectives the difference between abysmal and endless

is that abysmal is pertaining to, or resembling an abyss; unending; profound; fathomless; immeasurable while endless is having no end.

Endless is a synonym of immortal.

In obsolete terms the difference between immortal and endless

is that immortal is great; excessive; grievous while endless is without profitable end; fruitless; unsatisfying.

As adjectives the difference between immortal and endless

is that immortal is not susceptible to death; living forever; never dying while endless is having no end.

As a noun immortal

is one who is not susceptible to death.

As a verb ending

is .

As a noun ending

is a termination or conclusion.

As an adjective endless is

having no end.

Endless is a synonym of undying.

As adjectives the difference between endless and undying

is that endless is having no end while undying is permanent; never-ending; infinite.

As adjectives the difference between endless and unbounded

is that endless is having no end while unbounded is having no boundaries or limits.

As adjectives the difference between lengthy and endless

is that lengthy is having length; long and overextended, especially in time rather than dimension while endless is having no end.

As adjectives the difference between endless and steadfast

is that endless is having no end while steadfast is fixed or unchanging; steady.

As a noun brief

is letter (written message).

As an adjective endless is

having no end.

As adjectives the difference between endless and ongoing

is that endless is having no end while ongoing is continuing, permanent.

As a noun ongoing is

something that is going on; a happening.