clench (someone's) fists

Translations
сжать кулаки
He clenched his fists in anger.
Он сжал кулаки от злости.
Definitions
To tightly close one's hands into a ball, often as a response to anger, frustration, or determination.
Words
clench

verb
сжимать
someone

pronoun
чей-то
is

functional word
есть
fists

noun
кулаки