slantwise

vinosti diagonal, in a direction or orientation between cardinal axes
1858, (w), "Telling the Bees" in The Works of John Greenleaf Whittier, Vol. I, Narrative and Legendary Poems, http://www.gutenberg.org/files/9567/9567-h/9567-h.htmlink2H_4_0045

I can see it all now,—the slantwise rain / Of light through the leaves, / The sundown's blaze on her window-pane, / The bloom of her roses under the eaves.

(..) he had received a cut slantwise along one temple and cheek, leaving a long scar like a streak of dawn's light falling athwart the dark visage.