Mannerism/ˈmænərɪzəm/ Definition 1 of 2Pro Tip 1/3Personal Quirk A mannerism can be unique to an individual and easily noticeable. Her mannerism of giggling nervously made her stand out. Pro Tip 2/3Unconscious Action Mannerisms are often performed without conscious thought. He wasn't aware that tapping his foot was one of his mannerisms. Pro Tip 3/3Body Language Mannerisms can convey emotions or thoughts non-verbally. She has a mannerism of stroking her hair when she's unsure.