What is Googlebomb?

Googlebomb definition and meaning on Dictionary terms:
an effort to move a website to the top of search-engine results for a particular word or phrase, by creating a large number of links that contain this search text.

verb (used without object)
to engage in such an effort.

verb (used with object)
to make (a website, person, word, or phrase) a target of a Google bomb: His biography on the Web was Google-bombed with the search word “liar.”