'Unperturbed' definitions:

Definition of 'unperturbed'

From: WordNet
adjective
Free from emotional agitation or nervous tension; "the waiters were unflurried and good natured"; "with contented mind and unruffled spirit"- Anthony Trollope [syn: unflurried, unflustered, unperturbed, unruffled]

Definition of 'Unperturbed'

From: GCIDE