Open English Wordnet
Nouns
(n)composure, calm, calmness, equanimitysteadiness of mind under stress“he accepted their problems with composure and she with equanimity”
Verbs
(v)calm, calm down, quiet, tranquilize, tranquillize, tranquillise, quieten, lull, stillmake calm or still“quiet the dragons of worry and fear”
(v)calm, calm down, cool off, chill out, simmer down, settle down, cool itbecome quiet or calm, especially after a state of agitation“After the fight both men need to cool off.”, “It took a while after the baby was born for things to settle down again.”
(v)sedate, calm, tranquilize, tranquillize, tranquillisecause to be calm or quiet as by administering a sedative to“The patient must be sedated before the operation”
Adjectives
(s)calm, unagitated, serene, tranquilnot agitated; without losing self-possession“spoke in a calm voice”, “remained calm throughout the uproar”, “he remained serene in the midst of turbulence”, “a serene expression on her face”, “she became more tranquil”