Negative keywords are an important tool for any Google Ads campaign. They can make search and display campaigns more successful, by cutting unprofitable spend. Set at an account or campaign level, negative keywords give you fine control over where your ads appear.
You can think of negative keywords as a black-list of terms for which your ad will not show. You can specify these keywords as broad match, phrase match or exact match terms. This allows you to stop your ad displaying, even if your “positive keywords” target a broad range of search queries or display network pages.