1. to take one's leave; to excuse oneself; to leave; to depart
2. to resign (from); to step down; to leave (one's position); to quit
3. to decline; to turn down; to refuse
4. to do unwaveringly; to be prepared to do; to not mind doing
in the negative as ...を（も）辞さない, ...を（も）辞せず, etc.