How do I stop someone from spamming "Trending Search Terms"?

Our site is seeing something similar, but slightly different.

We appear to have some kind of bot performing a daily search on our forum for a few keywords.

Is there a way to block specific search terms?

Or, a way to link a search term to an IP address, then in turn to block that IP?

These, for example, are significantly skewing our search term data analysis: