Use the DROP GROUP statement to drop a role. DROP GROUP is an alias for DROP ROLE and is used to drop a role.
DROP GROUP
DROP ROLE
drop_group ::= DROP GROUP [ IF EXISTS ] role_name [ , ... ]
DROPGROUPIFEXISTS,role_name
See DROP ROLE for more details.
yugabyte=# DROP GROUP SysAdmin;
CREATE ROLE
ALTER ROLE
GRANT
REVOKE