I'm not familiar with such a term at all. You could always do a Google. I found quite a lot of results for it by just googling your question.
Google Bombing can be defined as an attempt at improving the ranking of a webpage through multiple links containing the same key phrase on other sites linking to that page.
Basically it is linking to a site using anchor text that does not appear on the page it is linking to, but the page ends up ranking solely on the anchor text. The most famous example of it was getting the George Bush Whitehouse page to rank for 'Miserable Failure'. http://google.about.com/od/socialtoolsfromgoogle/a/googlebombatcl.htm