Negative keywords applied in a video campaign overlay and inhibit the positive audience targeting. They allow us to shape who video discovery ads, and audience-targeted inline video ads serve to with more precision. In a video campaign, ads won’t show on videos that are related to the topic specified in each negative keyword.
In addition to using negative keywords, it may also be beneficial to exclude certain targeting audiences. “Negative” audiences can also improve campaign performance. Examples might include in-market audiences, interests, demographics such age, gender, income level, parental, and homeownership status.
More: blog articles about negative keywords.