A word of caution
Negating singular words will also negate their plural variations and vice versa.
Examples
Negating "turners" negates "spatula turner."
Negating "spatula-turner" negates "spatula turner."
To avoid negating good traffic, consider the following:
Do not assign this rule to ad groups with exact-match keywords.
Assign this rule to ads with the primary goal of discovering new keywords, such as automatic campaigns.
Whitelist important keywords under the Blacklist/Whitelist Rule.