one who reveals confidential information in return for money

impart knowledge of some fact, state or affairs, or event to, give character or essence to, act as an informer, transitive To communicate a knowledge of facts to, by way of accusation; to warn against anybody, to communicate facts by way of accusation against; to denounce, intransitive To acquaint (oneself) with knowledge of a subject, To be a formative or characterizing presence in; animate