not take (something) sitting down
To refuse to accept something unpleasant, unfortunate, or unjust without resistance, argument, or action. I just found out my wife has been cheating on me for the last year, and I'm not about to take it sitting down! I've been at this job for nearly 30 years and not once have I been given a raise. I'm telling you that I won't take this sitting down any longer!
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.