To clench means to squeeze or press something tightly together, usually your fists, teeth, or jaw. When you're nervous before giving a presentation, you might notice your hands clenching into fists without meaning to. When you're determined to push through something difficult, you might clench your teeth and keep going.

You can clench things in your hand: gripping a baseball bat tightly before swinging, or clenching a lucky coin in your palm during a tough test. The word suggests tension and effort, like your muscles are holding on tight and won't let go.

People often clench parts of their body when feeling strong emotions. Someone might clench their jaw when angry or frustrated, or clench their fists when excited or scared. Athletes sometimes clench their fists in victory after winning a close race. The physical act of clenching often reveals what someone's feeling inside, even when they're trying to hide it.

The word can also describe something gripping you: fear might seem to clench your stomach, or cold might seem to clench your chest. In these cases, it's describing how strong feelings can make your body tighten up, as if an invisible hand were squeezing you.