adj. 25B6; adjective
she's normally very placid : EVEN-TEMPERED, calm, tranquil, equable, equanimous, unexcitable, serene, mild, {cool, calm, and collected}, composed, self-possessed, poised, easy-going, level-headed, steady, unruffled, unperturbed, phlegmatic; informal unflappable.
a placid village : QUIET, calm, tranquil, still, peaceful, undisturbed, restful, sleepy.
excitable, bustling.