To disregard something means to pay no attention to it or to treat it as unimportant. When you disregard your teacher's instructions about showing your work on a math problem, you're ignoring advice that could help you. When a driver disregards a stop sign, they're dangerously pretending it doesn't exist.

Disregard suggests a choice to ignore something you're aware of. It's different from simply not noticing. If you walk past a friend without saying hello because you were lost in thought, that's not disregard. But if you deliberately ignore someone waving at you, that's disregarding them.

The word often appears in situations where ignoring something has consequences. A scientist who disregards safety procedures might cause an accident. A soccer player who disregards the referee's warnings might get ejected from the game. Sometimes disregarding advice turns out fine, but other times it leads to problems you could have avoided.

Disregard can also be a noun, meaning the act of ignoring: “Her complete disregard for the rules got her in trouble.” People sometimes say “disregard that” when they want you to ignore something they just said, like when they realize they've made a mistake.