Slantwise means at an angle or diagonal rather than straight across or straight up and down. If you walk slantwise across a rectangular field, you're cutting diagonally from one corner toward the opposite corner instead of walking along the edges. Rain that falls slantwise comes down at an angle, driven by the wind.

The word describes movement, position, or direction that tilts or leans. A carpenter might cut a board slantwise to create an angled edge. A crack might run slantwise across a window. You might glance slantwise at someone, looking at them from the corner of your eye rather than turning to face them directly.

Slantwise combines the idea of a slant (a slope or angle) with the word ending “-wise” (meaning “in the manner of”). It's a precise way to describe something that isn't quite straight, whether that's a path through the woods, a shaft of sunlight coming through blinds, or the way a kite string stretches toward the sky.