Tense boredom can be replaced with different phrases or words to describe the feeling of restlessness that one may experience. Some good synonyms for this phrase include anxious monotony, stressful tedium, or edgy ennui. Each of these replacements focuses on the same feeling of being trapped in boredom and unable to escape its grip, but with added nuances. Anxious monotony specifically highlights the underlying anxiety that one may feel when bored, while stressful tedium accentuates the sense of pressure that comes with being stuck in a rut. Edgy ennui, on the other hand, calls attention to the feeling of being on edge while feeling bored, as if something exciting might happen at any moment.