rubber stamp

Short definition from Wiktionary

Adjective

1. 1
   Of a person, organisation, or process, making decisions or approving matters routinely or without real power.

Noun

1. 1
   A 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.
2. 2
   A person or organisation that approves, routinely or as a formality, matters decided by some other person or organisation.
3. 3
   Alternative spelling of rubber stamp.

Verb

1. 1
   To process, approve or decide matters routinely rather than through careful consideration.
2. 2
   Alternative spelling of rubber stamp.