Source : Webster's Revised Unabridged Dictionary (1913)

Dateless \Date"less\, a.
   Without date; having no fixed time.

Source : WordNet®

dateless
     adj 1: having no known beginning and presumably no end; "the
            dateless rise and fall of the tides"; "time is
            endless"; "sempiternal truth" [syn: {endless}, {sempiternal}]
     2: of such great duration as to preclude the possibility of
        being assigned a date; "dateless customs"
     3: not bearing a date; "a dateless letter" [syn: {undated}]
     4: unaffected by time; "few characters are so dateless as
        Hamlet"; "Helen's timeless beauty" [syn: {timeless}]