Definition of "unhearing"

[She] flung herself / Down on the great King's couch, and writhed upon it, / And clench'd her fingers till they bit the palm, / And shriek'd out 'traitor' to the unhearing wall, […]

1859, Alfred Tennyson, “Elaine”, in Idylls of the King, London: Edward Moxon & Co., […], page 179

Camille said, as if unhearing, "Of course Apollo isn't with us permanently, you know!"

2001, Joyce Carol Oates, Middle Age: A Romance, paperback edition, Fourth Estate, page 272