1. To sob in a very loud, hysterical manner. She's been up in her room crying like a banshee ever since the breakup. I cried like a banshee the day we had to go put my dog to sleep.

2. To scream, howl, or screech in a very loud, high-pitched, and unsettling manner. Some animal has been crying like a banshee in the alleyway all night long. Kids, stop crying like a banshees back there! I need to focus on driving and I can barely hear myself think!