To disturb means to interrupt someone's peace, concentration, or rest. When you disturb your sister while she's reading, you break her focus with noise or questions. A “Do Not Disturb” sign on a hotel room door asks people not to knock or enter because someone inside wants quiet.

The word suggests disrupting something that was previously calm or settled. You might disturb a sleeping baby with a loud sneeze, or disturb the class when you drop your books. Teachers often ask students not to disturb others who are working.

Disturb can also mean to worry or upset someone emotionally. A disturbing news story might make you feel uneasy or troubled. If something disturbs you, it bothers your mind or emotions, not just your concentration.

In nature, you might disturb a hornet's nest (which is never a good idea), meaning you've disrupted something that was peacefully minding its own business. The related word disturbance describes the disruption itself: a disturbance in the hallway might mean noise or commotion that breaks the school's normal quiet atmosphere.