Definitions for datelessˈdeɪt lɪs
Random House Webster's College Dictionary
lacking a date; undated.
so old as to be undatable.
of permanent interest regardless of age.
having no social engagement.
Origin of dateless:
dateless, endless, sempiternal(adj)
having no known beginning and presumably no end
"the dateless rise and fall of the tides"; "time is endless"; "sempiternal truth"
of such great duration as to preclude the possibility of being assigned a date
not bearing a date
"a dateless letter"
unaffected by time
"few characters are so dateless as Hamlet"; "Helen's timeless beauty"
without date; having no fixed time