The Collaborative International Dictionary
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.
Douglas Harper's Etymology Dictionary
Wiktionary
a. 1 That cannot be remembered or has been forgotten. 2 (context loosely English) Whose origins have been forgotten; immemorial.
Usage examples of "immemorable".
Tarwater thus crouched, and, like his remote forebear, the child-man, went to myth-making, and sun-heroizing, himself hero-maker and the hero in quest of the immemorable treasure difficult of attainment.
So far, therefore, as the house of Armine was concerned, time flew during the next century with immemorable wing.
Although the term leopard, as applied to panthers, has the sanction of almost immemorable custom, I do not see why, in writing on the subject, we should perpetuate the misnomer, especially as most naturalists and sportsmen are now inclined to make the proper distinction.
It was expected of every member of our order that at least once during his lifetime he should make a pilgrimage to a certain monastery in Tibet, there to perform mystic rites in a secret sanctuary, where a sacred stone of immemorable antiquity was kept.
The multitudes to whom He preached were composed, as all multitudes are, of quite ordinary immemorable people.
Here and there clustered boulders washed by immemorable floods, but still leaving enough clear space for the passage of vehicles.
Muriel, and Ward--belonged to the myriads of the earth, to those numberless swarms that with ceaseless pullulation fill the streets of life with their grey immemorable tides.