Wiktionary
ballsiest
a. (en-superlativeballsy)
Usage examples of "ballsiest".
He alights next to me, saying, "Jack, that was the ballsiest half of an interview I ever heard.
Yet at the same time, Luigi was right, he had done his best, right from the start when they’d all walked into City Hall in the ballsiest escapade this side of the Trojan horse.