The word "most cliquish" refers to a group that is exclusive and insular, where only a select few are allowed in. Antonyms for "most cliquish" would include "inclusive," "welcoming," "open," "friendly," and "unified." These words describe environments that are accepting of others and encourage diversity in thought and experiences. An inclusive group would make all feel welcome, regardless of age, gender, race, or background. A welcoming group is an environment in which people feel invited to participate and contribute. An open group is one that freely shares ideas, opinions, and knowledge. A friendly group fosters friendliness and warmth, while a unified group demonstrates a sense of oneness and collaboration towards a common goal.