The definition of brown nose is a person who does or says what he thinks is necessary to get approval or favor from people who are in positions of power or authority.
(noun)An example of a brown nose is someone who brings his boss coffee every morning and tells him how nice he looks.
To brown nose is to do or say things to seek approval or be looked at favorably by someone who is in a position of power or authority.
(verb)An example of to brown nose is when you say to your boss "you look very nice" and give your boss a coffee every morning.