1. cruel, unfair, hurtful; against the rules of sportsmanship

1. Saying he wasn’t very good in math just because he got a 99 on the test was really hitting below the belt.

2. John told Robert about the job he was planning to apply for and Robert went out and got it himself! Robert doesn’t play fair. He hits below the belt.

3. Mary introduced Sally to her boyfriend, Mike, and before she knew it, Sally and Mike were dating. That was below the belt.