Overkill is using way more force, effort, or resources than a situation actually needs. When you bring ten pencils to a test that only has five questions, that's overkill. When someone writes a twenty-page report for an assignment that only asked for two pages, that's overkill too.

If you need one tool but bring fifty, that's overkill. Today we use it more broadly for any situation where someone goes overboard.

Overkill often happens when people want to be extra sure of success or when they misjudge how much is needed. A student might study twelve hours for a simple spelling quiz (overkill), while thirty minutes would have been plenty. A cook might add a whole cup of salt to a recipe that needs just a pinch.

Sometimes overkill is harmless, like decorating every inch of your locker when a few pictures would do. Other times it wastes resources or energy that could be used elsewhere. The key is matching your response to what the situation actually requires. Bringing a calculator to solve 2+2 is overkill. Bringing one to a calculus exam makes perfect sense.