Hardball/ˈhɑːrdbɔːl/ Definition 1 of 2Pro Tip 1/3Tough Negotiations Indicates a no-compromise attitude in discussions or deals. He's playing hardball to get the best contract. Pro Tip 2/3Assertive Tactics Implies using strong, confident strategies to persuade others. She is known for playing hardball with competitors. Pro Tip 3/3Serious Intent Shows a serious determination to achieve an objective. When they started playing hardball, we knew negotiations were serious.