From Longman Dictionary of Contemporary Englishsilent partnerˌsilent ˈpartner noun [countable] American English BBCsomeone who owns part of a business but is not actively involved in the way it operates SYN sleeping partner British English
Examples from the Corpus
silent partner• He has a silent partner and some name-brand advertisers.• Whenever a dad plays, there is usually a mom playing, who may not realize she is a silent partner.• He wants to know were you my silent partner. 