You can drop custom roles, but not default roles.
Prerequisites
You have the DROP ANY ROLE system privilege and the WITH ADMIN OPTION privilege on the role to be dropped.
For information about how to view your privileges, see View user privileges. If you do not have the required privileges, contact the administrator. For information about how to grant privileges to a user, see Modify user privileges.
Considerations
When you drop a role, the system revokes the role from all users and roles that have been granted the role and then drops the role from the database.
Notice
Dropping a role does not affect user sessions in which the role has already been enabled. However, after the role is dropped, if a new user session is established, the role cannot be enabled in the new user session.
Syntax and examples
The syntax is as follows:
obclient> DROP ROLE role_name;
Here is an example:
obclient> DROP ROLE role1;
Query OK, 0 rows affected
For more information about the DROP ROLE statement, see DROP ROLE.