[adjective] having no known beginning and presumably no end; "the dateless rise and fall of the tides"; "time is endless"; "sempiternal truth" Synonyms:endless, sempiternal
[adjective] of such great duration as to preclude the possibility of being assigned a date; "dateless customs"
[adjective] not bearing a date; "a dateless letter" Synonyms:undated
[adjective] unaffected by time; "few characters are so dateless as Hamlet"; "Helen's timeless beauty" Synonyms:timeless