Learn English – What would be next after minor, major, ….

single-word-requests

I'm looking for a word that would describe a third category following a "minor" and "major" category. (For compatibility reasons it won't do to insert a middle category of "moderate" or the like.) Example usage:

After fighting past several minor encounters, and a few major
encounters, the adventurers finally made contact with the _____ encounter.

Best Answer

If it's implied that there are no further obstacles - final.

If it's implied that there's no greater obstacle - supreme.

If it's implied that there's no passing the obstacle - overwhelming.

If it's required to keep some kind of hierarchy - capital.