clenched

(verb) hold in a tight grasp. Synonyms: clench, clinch. Example: "Clench a steering wheel."

(verb) squeeze together tightly. Synonyms: clench. Example: "Clench one's jaw."

(adj) closed or squeezed together tightly. Synonyms: clinched. Examples: "A clenched fist." "His clenched (or clinched) teeth."