Hush Money

bribe to keep silent about something

For a general description of the term, see hush money. Hush Money is a 1931 film featuring Joan Bennett, Hardie Albright, Owen Moore, Myrna Loy, and George Raft. The movie was directed by Sidney Lanfield.
See more at Wikipedia.org...

Hush money is an informal term for financial incentives or rewards offered in exchange for not divulging information.Hush money is different than blackmail, which is a type of threat made by someone who has compromising information about someone else. In the case of hush money the person who does not want the information divulged approaches the person who knows it.Hush money can be offered for both criminal and non-criminal reasons, though the term is used more often in criminal situations, or in a derogatory sense.
See more at Wikipedia.org...

Noun
1. a bribe paid to someone to insure that something is kept secret
(hypernym) bribe, payoff

a payment made to an individual to keep them from disclosing certain information to others. Often illegal.