Definition of "arrowy"

Now the Storm begins to lovver, / (Haſte, the loom of Hell prepare,) / Iron-ſleet of arrovvy ſhovver / Hurtles in the darken'd air.

1761 (date written), [Thomas] Gray, “Ode VIII. The Fatal Sisters. From the Norse Tongue.”, in The Poems of Mr. Gray. […], York, Yorkshire: […] A. Ward; and sold by J[ames] Dodsley, […]; and J. Todd, […], published 1775, stanza 1, page 44

I saw him in his boat, which shot across the waters with an arrowy swiftness, and was soon lost amidst the waves.

1818, [Mary Shelley], chapter III, in Frankenstein; or, The Modern Prometheus. […], volume III, London: […] [Macdonald and Son] for Lackington, Hughes, Harding, Mavor, & Jones, page 49