(someone) is (someone's) right hand man

Your "right hand man" is the person who helps you out the most. It's not like an assistant, but more like a "second in command". This is the person you trust and depend on.

By the way, when you're talking about a woman who holds this position, you might use the phrase "right hand woman", but you might also use "right hand man" anyway.

This phrase appears in these lessons: