1. To say no to something, to not accept something, or to get rid of something because you do not like it at all; to dismiss, reject or discard something. English = reject, dismiss.
2. To refuse to do something or to stop doing something because you think it is silly, unimportant, too difficult or a waste of time.
3. To give up on doing something because you think it is too difficult or because you really do not want to do it at all. English = give up. Idiomatic English = throw in the towel.