(a.) Composed or tranquil in mind, manner, etc.; undisturbed.

aloof assured balanced calm collected composed confident controlled cool detached dignified easy easygoing equanimous equilibrious even-tempered firm-minded forward imperturbable importunate independent levelheaded peaceful placid poised pushy recollected refined reserved self-asserting self-assertive self-assured self-confident self-contained self-controlled self-expressive self-restrained serene strong-minded strong-willed together tranquil undisturbed unflappable unperturbed unruffled well-balanced