9
confident
6
calm
5
relaxed
5
self-confident
4
collected
4
courageous
4
peaceful
3
imperturbable(adjective, calm, collected)
2
cool
2
easygoing
2
laid-back
2
nerveless
2
self-assured
2
serene
2
tranquil
2
unexcitable
2
unflappable
2
unworried
1
happy-go-lucky
1
provide
10 years ago|1.4k views|share |citing 
APASmart Define. (2016). jittery thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/jittery/thesaurus/antonyms
ChicagoSmart Define. 2016. "jittery thesaurus" https://smartdefine.org/jittery/thesaurus/antonyms (accessed September 24, 2026).
HarvardSmart Define 2016, jittery thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/jittery/thesaurus/antonyms>.
MLASmart Define. "jittery thesaurus" 23 March 2016. Web. 24 September 2026. <https://smartdefine.org/jittery/thesaurus/antonyms>