Main Entry: clench

Pronunciation: \ˈklench\

Function: transitive verb

Etymology: Middle English, from Old English -clencan; akin to Old English clingan to cling

Date: 13th century

1 : clinch 2
2 : to hold fast : clutch <clenched the arms of the chair>
3 : to set or close tightly <clench one's teeth> <clench one's fists>

— clench noun