Clench
WordNet
noun
(1) The act of grasping
"He released his clasp on my arm"
"He has a strong grip for an old man"
"She kept a firm hold on the railing"
(2) A small slip noose made with seizing
verb
(3) Squeeze together tightly
"Clench one's jaw"
(4) Hold in a tight grasp
"Clench a steering wheel"