Reverse search engine optimization - unranking for keyword or keyword phrases you work well for. Why in the world would you want to rank less in the search engines? Well, people have their reasons. We actually covered this topic twice in the six plus years of writing about SEO topics:
A recent Google Webmasters Help thread has a question from an SEO blogger named Gab Goldenberg of SEO ROI. He said he ranks too well for [advertising presentation] in Google and wants to not rank as well.
Why does he want to rank lower? He feels that his page that ranks well for advertising presentation is not what people are really looking for. This leads to those readers being dissatisfied with what they see and also leads to a high bounce rate. Some believe bounce rates influence rankings of the entire site, so it might be detrimental the rest of the site to have a high bounce rate on a specific page (I don't believe that). But the main reason Gab wants to rank lower is because he only wants happy readers.
Googler, JohnMu, offered advice on how to rank lower in Google. John said:
If you rank for a phrase that you don't want to rank for, there's not much you can do other than make sure that your content does not include this phrase. Adjusting the description meta-tag and the title element to give more information about what you are really writing about can be helpful as well, although this may not affect your ranking for that phrase. Adding a "not" qualifier won't really help to change the ranking, but it might help users who are looking for something particular.
One trick you could try is to replace individual letters with alternate glyphs that look very similar. For instance, you could replace a lower case "L" with the number "1" (or use cyrillic characters that look very similar, eg "e"/"е", "r"/"г", "i"/"і", etc.). While this would make it harder for us to understand your content (say if someone wanted to use Google Translate to read it in their own language), it would likely also prevent your content from ranking for those words.
Simply, complete unoptimize that page. Or try to target the page towards a more relevant keyword phrase.
Forum discussion at Google Webmasters Help.