Placid/ˈplæsɪd/ Definition 1 of 3Pro Tip 1/3Non-Reactiveness It can describe someone who stays calm and doesn't respond to provocation. Despite the heated debate, her placid nature kept the conversation civil. Pro Tip 2/3Emotional Stability Implies emotional control and often seen as a positive trait. His placid demeanor during the crisis reassured everyone. Pro Tip 3/3Mistaken for Indifference Can sometimes be mistaken for lack of interest or enthusiasm. Her placid response to the news puzzled her friends who expected more excitement.