undated vs dateless

undated and dateless both are adjectives.

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

As adjectives, undated and dateless are synonyms defined as:

undated (adjective)	dateless (adjective)
not bearing a date	having no known beginning and presumably no end
	unaffected by time
	not bearing a date
	of such great duration as to preclude the possibility of being assigned a date