CLENCH

[verb] [T] - to close or hold very tightly, often in a determined or angry wayThe old man clenched his fist and waved it angrily at the girls who had climbed over his fence."Get out of here," she said through clenched teeth.Sam clenched the toy car tightly in his hands, and wouldn't give it to his brother.The boy climbed the palm tree with a knife clenched in/between his teeth and began to cut down the coconuts.