1.nounA piece of rubber or similar material with a design or text carved or molded for the purpose of transferring ink or dye to imprint that design on another object.
"The library had a rubber stamp to imprint the due date."
2.nounA person or organisation that approves, routinely or as a formality, matters decided by some other person or organisation.
3.verbTo process, approve or decide matters routinely rather than through careful consideration.
"They usually just rubber stamp orders under $100."
4.adjectiveOf a person, organisation, or process, making decisions or approving matters routinely or without real power.