Negative keywords are used to eradicate unqualified traffic. For example, if you are running an advertising campaign for ‘High Value Custom Furniture’, adding ‘Free’, ‘Cheap’ or ‘Bargain’ as your negative keywords will not include your Ad in search results for queries like ‘Free Furniture’, ‘Cheap Furniture’, or ‘Bargain Furniture’. Note- It is one of the most important PPC interview questions and your concept has to be clear about the same.