Drawing a blank

I'm trying to think of a word for some-
thing but I can't think of that word.
                                                              There must
exist a word for that.                       I hope that some-
one knows that word that's blanked whom I could trust!

The way a lost
word

will come back
unbidden.

You're not interested
in it now,

only
in knowing
where it's been.

from "Unbidden" by Rae Armantrout