Today we have one of those pairs that are often confused. It makes my teeth clench every time I see them used improperly.

Clinch is to fix or secure (as a nail or bolt) by bending down or flattening the end that protrudes. This definition gave rise to the now more common use of clinch—to settle definitely and conclusively. It’s now a very common sports term when a team or person secures a title or victory.

Clench means to close tightly, or to grasp or grip tightly. It’s also a noun referring to a tight grip or grasp.

This is also a great article comparing the two: