wikipedia

Any change or edit that manipulates content in a way that deliberately compromises Wikipedia's integrity is considered vandalism. The most common and obvious types of vandalism include additions of obscenities and crude humor; it can also include advertising and other types of spam.[81] Sometimes editors commit vandalism by removing content or entirely blanking a given page. Less common types of vandalism, such as the deliberate addition of plausible but false information, can be more difficult to detect. Vandals can introduce irrelevant formatting, modify page semantics such as the page's title or categorization, manipulate the article's underlying code, or use images disruptively.