how to "revoke" a "GRANT OPTION" from an mysql user/database?
Just as usual...

root@localhost:playground &gt; grant select, grant option on playground.* to asdf@localhost identified by 'asdf';
Query OK, 0 rows affected (0.02 sec)

root@localhost:playground &gt; show grants for asdf@localhost;
+-------------------------------------------------------------------------------------------------------------+
| Grants for asdf@localhost                                                                                   |
+-------------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'asdf'@'localhost' IDENTIFIED BY PASSWORD '*7F0C90A004C46C64A0EB9DDDCE5DE0DC437A635C' |
| GRANT SELECT ON `playground`.* TO 'asdf'@'localhost' WITH GRANT OPTION                                      |
+-------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)

root@localhost:playground &gt; revoke grant option on playground.* from asdf@localhost;
Query OK, 0 rows affected (0.00 sec)

root@localhost:playground &gt; show grants for asdf@localhost;
+-------------------------------------------------------------------------------------------------------------+
| Grants for asdf@localhost                                                                                   |
+-------------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'asdf'@'localhost' IDENTIFIED BY PASSWORD '*7F0C90A004C46C64A0EB9DDDCE5DE0DC437A635C' |
| GRANT SELECT ON `playground`.* TO 'asdf'@'localhost'                                                        |
+-------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)


The manual is also as always very helpful.