In Chinese culture, the concept of a 敌手 is often viewed as a necessary component for growth and self-improvement. Having a worthy rival pushes you to sharpen your skills, test your limits, and ultimately become stronger. This idea is a common trope in classic literature, martial arts (Wuxia) stories, and historical epics like “Romance of the Three Kingdoms,” where great generals and heroes are defined by the caliber of their rivals. This contrasts with the often more negative Western concept of a “nemesis” or “arch-enemy,” which typically implies pure animosity and a desire for the other's total destruction. While a 敌手 is an adversary, the relationship can be built on mutual, albeit grudging, respect. The underlying value is that a strong opponent doesn't just threaten you; they validate your own strength. To be considered a 敌手 by someone great is itself a high compliment.
敌手 is a relatively formal and literary term, but it's used in various modern contexts to add a sense of gravity to a rivalry.
While the more common and neutral word 对手 (duìshǒu) is used more frequently in casual conversation, 敌手 is chosen when you want to emphasize that the opponent is a significant, challenging, and worthy one.