ORA-65040: Operation not allowed from within a pluggable database

 I need to drop some package and synonyms from a PDB. When I attempted to do, I faced the below issue.

Quick surf on the metalink leads to the solution.

Warning: Object owned by SYS user should not be dropped without understanding its impact and proper backup.

When you created the synonym with the schema name also appended with the object name, then it can be dropped like below.

drop public synonym "TFGADMIN.DBMS_OUTPUT";