Not to disturb someone or something
That is the correct spelling of the word "unperturbed" (unaffected, calm).
He doesn't seem unperturbed by the comment Eric made.
Composed, undisturbed, unruffled, or placid. Those words mean unperturbed.
unfazed
unperturbed
びくともし
The boy was remarkably unperturbed by the terrible news.
The nasty argument left her unperturbed. (She was not bothered)
Despite the chaos around her, she remained unperturbed and continued to focus on her work.
"Unperturbed" means not perturbed or disturbed; calm and composed in the face of adversity or frustration.
Self-confident would work. So would unperturbed. Source: The thesaurus.
calmtranquilplacidundisturbedunstirredcollectedserene