A man who provides counsel and advice to the head of a Mafia crime family is an example of a consigliere.
Origin of consigliereIt, counselor, advisor from consiglio, advice from Classical Latin consilium, counsel
Origin of consigliereItalian from Latin cōnsiliārius from cōnsilium advice
Italian consiglio, "advice", "counsel", from Latin consilium.
Entered the popular English lexicon through Mario Puzo's “Godfather” novels and the subsequent films made from them.