To negate means to cancel something out or make it have no effect. When you negate something, you essentially erase or reverse it, like hitting an undo button.

In math, you negate a number by changing its sign: negating 5 gives you -5, and negating -3 gives you 3. Each number negates the other, adding up to zero.

In everyday life, one action can negate another. If you practice piano all week but then skip your lesson, you've negated some of your progress. If a soccer team scores a goal but then gets a penalty that takes it away, the penalty negated their score. When a kind gesture is followed by a mean comment, the meanness can negate the kindness.

When you negate a statement, you're saying it's not true. If someone claims “nobody likes math,” you could negate that statement by pointing out all the engineers, scientists, and mathematicians who love it.

Negation is the noun form. In logic and debate, negation means proving something false or showing its opposite.