To vanquish someone means to beat them completely — so completely that they cannot fight back or come back. It is not used for a small win. If your team wins a football game 2-1, nobody says you vanquished the other team; you just beat them. But an army that destroys another army, a hero who kills the monster at the end of the story — that is vanquish. The word is old and grand-sounding. Most people never say it in normal talking. You meet it in history books, in fantasy stories, in film titles, in the Bible, in sports writing where the writer is trying to sound dramatic. If you use it about something small, it sounds funny, and sometimes people do that on purpose as a joke: "I have vanquished the last piece of cake." There is one more use that is a bit less warlike: you can vanquish a feeling, especially fear or doubt or sadness. "She vanquished her fear of flying." This means the feeling is gone for good, not just quiet for one day. The enemy has become something inside you, but the idea is the same — total, final defeat. Grammar note: it takes an object. You vanquish someone. You cannot just "vanquish" with nothing after it.

徹底擊敗、征服（打到對方再也翻不了身）；用在恐懼、疑慮時是「克服、戰勝」