A vanquish is when someone or something completely defeats an opponent, and also means to overcome or conquer something difficult.
When we use the word "vanquish", we often talk about big challenges or strong enemies that need to be defeated. For example, imagine a brave knight fighting against a fierce dragon - he might need to vanquish it with his sword. We can also use this word for non-physical battles, like vanquishing an addiction or overcoming a difficult problem at work. Sometimes we say someone has vanquished their fears or doubts, which means they've finally found the courage to face them and move forward.
(transitive) To defeat (someone); to overcome.
