The term 'exclude from a group' can be summarized by the 9-letter crossword solution 'BLACKBALL'. Blackballing is a process of exclusion or ostracism, where an individual or group is excluded from a society or organization. This exclusion is usually based on the disapproval of the individual or group's beliefs or actions. Blackballing is often used as a form of punishment or to prevent someone from joining a particular group.