forgetful

Unable to remember things well; liable to forget.

Nor has Dalua part or mention in the antique legend. Like other ancient things, this divinity hath come secretly upon us in a forgetful time, new and strange and terrible, though his unremembered shadow crossed our way when first we set out on our long travel, in the youth of the world.

Dropping some of the input's structure or properties before producing an output.

a forgetful mapping; a forgetful functor