The phrase "on edge" refers to a state of nervousness or anxiety. There are several synonyms for this phrase, including "anxious," "nervous," "edgy," "jittery," "tense," and "uneasy." These words all convey a sense of discomfort or agitation, often caused by a stressful situation or event. Other synonyms that are similar in meaning include "apprehensive," "worried," "fidgety," "restless," "irritable," and "jumpy." It's important to recognize these emotions in oneself or others and take steps to mitigate them, such as deep breathing, mindfulness exercises, or seeking support from loved ones or professionals.