endless vs dateless

endless and dateless both are adjectives.

Word	Noun	Adjective	Verb	Adverb
endless	No	Yes	No	No
dateless	No	Yes	No	No

As adjectives, endless and dateless are synonyms defined as:

Other synonyms of endless include sempiternal.

endless (adjective)	dateless (adjective)
having the ends united so as to form a continuous whole	having no known beginning and presumably no end
having no known beginning and presumably no end	unaffected by time
tiresomely long; seemingly without end	not bearing a date
infinitely great in number	of such great duration as to preclude the possibility of being assigned a date