* The general public: If you're thinking of a coterie as a small, exclusive group, the antonym could be the general public, the masses, or the populace.
* Broad community: You could also use terms like broad community, wide range of people, or diverse group.
* Open group: If you want to emphasize the exclusivity of a coterie, you could use open group, inclusive group, or welcoming group.
* Large group: If the focus is on the size, then large group, vast assembly, or huge crowd would work.
The best antonym will depend on the specific meaning and context you're aiming for.