balls [ bɔlz ] noun IMPOLITE
1. ) uncount confidence and the ability to deal with dangerous or difficult situations: NERVE:
It takes balls to quit your job like that.
2. ) plural TESTICLES
3. ) uncount nonsense
have someone by the balls
to have complete control over someone, so that they have to do what you want

Usage of the words and phrases in modern English. 2013.