Words/phrases that prevent your ad from appearing in Amazon search results.
Negative Keywords are words or phrases that prevent your ad from appearing on Amazon's search engine results page when those terms are in a Search Term (the customer's search query).
Negative keywords can be added at the campaign or ad group level.
Example: adding "pick" as a negative phrase will eliminate "guitar pick," "tooth pick," "pick," and "the quick brown fox."
Example: adding "pick" as a negative exact will only eliminate "pick," and not the multiple word variations.