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unfazed

[uhn-feyzd] / ʌnˈfeɪzd /
ADJECTIVE
not dismayed
Synonyms
STRONGEST
undaunted unperturbed
STRONG
calm collected composed cool nonchalant
WEAK
casual detached placid serene tranquil unvexed unworried
Antonyms
STRONGEST
anxious perturbed upset worried
STRONG
disoriented frazzled
WEAK
frantic overinvested panicked

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.