Collocations for clench - verb

firmly, tight, tightly
His jaw was clenched tight.
His jaw was tightly clenched.

involuntarily, unconsciously
Her hands clenched involuntarily.

together
She sat with hands clenched together in her lap.

clenched between sb's teeth
He had a pipe clenched between his teeth.

Clench is used with these nouns as the subject:
fist, hand, jaw, muscle, stomach

Clench is used with these nouns as the object:
finger, fist, hand, jaw, muscle, tooth