1. A stamp of rubber for making imprints
2. A person who echoes or imitates others
3. A mostly powerless yet officially recognized body or person that approves or endorses programs and policies initiated usually by a single specified source
4. Routine authorization of an action without questions.

1. To approve automatically.
2. To stamp with a rubber-stamp, usually an indication of official approval on a document; SYN. handstamp.