Shear means to cut something with a large scissor-like tool, especially wool from a sheep or hedges in a garden. When farmers shear their sheep in spring, they carefully clip away the thick winter coat of wool, leaving the sheep cooler and providing wool for sweaters and blankets. The animal isn't hurt: it's like getting a necessary haircut. Gardeners use shears (long-bladed scissors) to trim bushes into neat shapes or cut through thick branches.

The word also appears in science and engineering. When forces push or pull on an object in opposite directions, like sliding a deck of cards so the layers shift, that's called shear. Wind creates shear forces when it blows at different speeds at different heights, which pilots watch carefully. Earthquakes cause rocks to shear past each other along fault lines.

You might hear the past participle shorn in phrases like “shorn of his dignity,” meaning stripped of something important, the way a sheep is stripped of its wool. The word shear sounds exactly like sheer (meaning pure, steep, or transparent), but they're completely different words with different meanings.