1. quiet, motionless. 3. placid, peaceful, serene, self-possessed. Calm, collected, composed, cool imply the absence of agitation. Calm implies an unruffled state, especially under disturbing conditions: calm in a crisis. Collected implies complete inner command of oneself, usually as the result of an effort: He remained collected in spite of the excitement. One who is composed has or has gained dignified self-possession: pale but composed. Cool implies clarity of judgment along with apparent absence of strong feeling or excitement, especially in circumstances of danger or strain: so cool that he seemed calm. 7. still, quiet, tranquilize; allay, assuage, mollify, soothe, soften.