The antonyms for the word "most unflustered" include insecure, uneasy, agitated, disturbed, and bothered. In contrast to being unflustered, someone who is insecure may lack confidence, feel uncertain, or doubt their abilities. An uneasy person may feel uncomfortable or anxious, while an agitated person may be irritable or restless. Someone who is disturbed may be upset, troubled, or unsettled, while a bothered person may feel annoyed or bothered by something. These antonyms serve to highlight the contrast between being unflustered and feeling negative emotions or lacking confidence, demonstrating the importance of staying calm and collected in challenging situations.