What is a synonym for the word approval?

Here are some synonyms for "approval", depending on the context:

Formal:

* Sanction

* Authorization

* Endorsement

* Consent

* Ratification

* Permission

Informal:

* Go-ahead

* OK

* Thumbs up

* Green light

* Sign-off

Other:

* Acceptance

* Favor

* Commendation

* Praise (if it implies positive judgment)

The best synonym will depend on the specific context and the nuance you want to convey.