1. People who bite their fingernails, typically as a nervous habit.
Usage: plural form; informal
2. Events or situations that are extremely suspenseful or anxiety-inducing.
Usage: plural form; informal; figurative

Examples

• Many nailbiters develop the habit during stressful periods in school.
• The final minutes of the game were real nailbiters for the fans.
• Nailbiters often don't realize they're doing it until their fingers start to hurt.
• Those playoff matches were absolute nailbiters—nobody knew who would win.
• Some nailbiters wear gloves to help break the habit.
• The election results came down to a few nailbiters in key states.