Testy means irritable, impatient, or easily annoyed. When someone is testy, small things bother them more than usual, and they might snap at others or respond with sharp words. A testy teacher might lose patience quickly when students talk during a lesson. Your normally cheerful friend might become testy after a bad night's sleep, getting annoyed by jokes that would usually make them laugh.

The word describes a temporary mood more than a permanent personality. Your dad might be testy after a long, frustrating day at work, but he's not a testy person generally. Athletes sometimes get testy during tough competitions when the pressure builds. A testy reply is short and irritated, like “Fine!” or “Whatever!” instead of a calm, friendly response.

People often become testy when they're tired, hungry, stressed, or dealing with too many problems at once.