imperturbable

adj. Unexcitable;calm;unflustered

synonyms:
nerveless
assured
composed

Antonyms:
excitable
irritable
jittery

Sentences:
Even though it was going to be a hard test, she was imperturbable because she studied.
Even though it was the old man's birthday, he was imperturbable because he was turning so old.
Big image
Phoebe's triplets (friends) 5x03