endlessly

As an adverb endlessly

is in an endless manner; continuously without limit.

As an adjective undefined is

lacking a definition or value.

Everlastingly is a related term of endlessly.

As adverbs the difference between everlastingly and endlessly

is that everlastingly is in an everlasting manner; so as to be everlasting while endlessly is in an endless manner; continuously without limit.

As adverbs the difference between unendingly and endlessly

is that unendingly is without end; eternally; in an unending manner while endlessly is in an endless manner; continuously without limit.

is likely misspelled.

has no English definition.

As an adverb endlessly

is in an endless manner; continuously without limit.

As an adverb endlessly

is in an endless manner; continuously without limit.

As an adjective interminable is

existing or occurring without interruption or end; ceaseless, unending.

As adverbs the difference between forever and endlessly

is that forever is (duration) for all time, for all eternity; for an infinite amount of time while endlessly is in an endless manner; continuously without limit.

As a noun forever

is an extremely long time.

As adverbs the difference between lastly and endlessly

is that lastly is (sequence) while endlessly is in an endless manner; continuously without limit.

Ceaselessly is a related term of endlessly.

As adverbs the difference between ceaselessly and endlessly

is that ceaselessly is without ceasing while endlessly is in an endless manner; continuously without limit.

Interminably is a related term of endlessly.

As adverbs the difference between interminably and endlessly

is that interminably is in an interminable manner while endlessly is in an endless manner; continuously without limit.

Unchangeably is a related term of endlessly.

As adverbs the difference between unchangeably and endlessly

is that unchangeably is in a way that cannot be varied]], or [[change#verb|changed while endlessly is in an endless manner; continuously without limit.