A bribe paid to someone to insure that something is kept secret WordNet 3.0 & Open English WordNet

Hush money is a term for an arrangement in which one person or party offers another an attractive sum of money or other enticement, in exchange for remaining silent about some illegal, stigmatized, or shameful behavior, action, or other fact about the person or party who has made the offer. Wikipedia

Form of bribery in which someone offers another money or other enticement, in exchange for remaining silent about some illegal/stigmatic/shameful behavior/action/… Wikidata

A bribe to maintain secrecy (to prevent bad publicity or to prevent the discovery of a crime). Wiktionary

Bribe to maintain secrecy. Wiktionary (translation)