stand up to someone or something
to take a stand against someone or something; to hold one's ground or principles in the face of a challenge by someone or something. He is a tough customer, and you have to learn to stand up to him. Can the witness stand up to questioning by the prosecution?
See also: stand, up
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
stand up to somebody/something
to oppose someone or something without fear I know Jim would stand up to absolutely anyone, even his boss, if he believed he was right about something.
See also: stand, up
Cambridge Dictionary of American Idioms Copyright © Cambridge University Press 2003. Reproduced with permission.