To slant is to tilt or slope sharply to one side. Many streets in San Francisco are so steep that they slant dramatically upward.
You can slant the brim of your hat down to keep the sun out of your eyes, and the sun itself can slant at a lower angle (or slant), forcing you to put on your dark sunglasses. There's also the slant that means "show bias," the way a newspaper reporter does when she slants a story in favor of one political party over another. Slant was originally slenten, "slip sideways," from a Germanic root.