Self-possessedly, meaning having self-control and composure, can be described by antonyms like agitated, nervous, restless, and uneasy. These words signify a lack of confidence and stability in demeanor. They are opposites to self-possessedly because individuals who are self-possessed are calm, confident, and steady. In contrast, those who are agitated, nervous, restless, or uneasy may lack control over their thoughts and actions. Furthermore, antonyms like unstable, unpredictable, erratic, and impulsive also signify a lack of self-control, which makes them opposite to self-possessedly. Antonyms for self-possessedly show the variety of ways individuals can be affected by a lack of composure and self-control.