John Ashbery uses the word "cimmerian" in his 22 page-long Poem called A WAVE, which is printed in his book, also titled A WAVE, published by Viking Press (New York) in 1984. It can be found on page 81. I will quote only a part of the 10-line-long sentence in which it appears:
"...So always there is a small remnant Whose lives are congruent with their souls And who ever afterward know no mystery in it, the CIMMERIAN moment in which all lives, all destinies And incompleted destinies were swamped As though by a giant wave that picks itself up Out of a calm sea and retreats again into nowhere Once its damage is done."
Blurb on the back of A Wave by John Ashbery says: "The charm of Ashbery's urbane style—so various, so beautiful, so new—persists throughout A Wave, and will induce the rereadings the poem demands. It is a style that resists, in its glowing reflectiveness, the approaching darkness of the cimmerian moment." —Helen Vendler, The New York Review of Books