Clenched fists are a physical manifestation of internal emotions such as anger, frustration, and tension. However, there are a variety of synonyms one can use to describe this physical gesture. Some alternatives include squeezed fists, tight fists, gripped fists, balled fists, compressed fists, and closed fists. Each variation highlights the same action of curling one's fingers and thumb into a tight ball. Other expressions that convey a similar meaning but a slightly different connotation include knotted hands, tensed fingers, and furled fists. Using synonyms adds variety and depth to your writing, allowing you to convey emotion in a more nuanced and impactful way.