Add the following to the <head></head> section of your page.
<meta name="robots" content="NoIndex, NoFollow" />
<meta name="googlebot" content="NoIndex, NoFollow" />
Or add a robots.txt file on your server. See...
http://www.robotstxt.org/wc/norobots.html
I have a better idea though... Elaborate on what you already have and if you get alot of traffic for those terms optimize the pages and make something interesting out of them. That way you can capitalize on the extra traffic instead of it being a nuisance.