immemorable

from The Collaborative International Dictionary of English v.0.48

Immemorable \Im*mem"o*ra*ble\, a. [L. immemorabilis; pref. im-
   not + memorabilis memorable: cf. F. imm['e]morable. See
   {Memorable}.]
   Not memorable; not worth remembering. --Johnson.
   [1913 Webster]