Behavioral quirks are small, often unconscious habits or MANNERISMS that people display in their behavior. MANNERISMS, which is a 10 letter word for this crossword, is defined as a way of behaving, speaking, or writing that is characteristic of a particular person. TICS, which is a 4 letter word for this crossword, is defined as a sudden, repetitive, nonrhythmic motor movement or vocalization involving discrete muscle groups. Both MANNERISMS and TICS are examples of behavioral quirks.