Suppression means forcefully holding something back or keeping it from happening. When you suppress something, you push it down or prevent it from coming out or being seen.

You might suppress a laugh during a serious moment, pressing your lips together and trying not to let the giggle escape. A government might suppress information by preventing newspapers from publishing certain stories. During a fire, firefighters work on fire suppression, stopping the flames from spreading. In medicine, doctors sometimes prescribe drugs that suppress your immune system to prevent your body from rejecting a transplanted organ.

The word carries a sense of force or effort. You don't just ignore something when you suppress it; you actively work to keep it contained. A country might suppress a rebellion by using military force. A person might suppress their anger, consciously pushing down their frustration instead of expressing it. Sometimes suppression is necessary and helpful, like suppressing a cough during a concert. Other times it can be harmful, like when powerful people suppress the truth to hide wrongdoing.

Related words include suppress (the verb), suppressed (the adjective describing something that has been held back), and suppressor (something or someone that suppresses). The opposite of suppression is expression or release, letting something out freely.