|This page in a nutshell: Intentionally making abusive edits to Wikipedia will result in a block.|
On Wikipedia, vandalism has a very specific meaning: editing (or other behavior) deliberately intended to obstruct or defeat the project's purpose, which is to create a free encyclopedia, in a variety of languages, presenting the sum of all human knowledge.
The malicious removal of encyclopedic content, or the changing of such content beyond all recognition, without any regard to our core content policies of neutral point of view (which does not mean no point of view), verifiability and no original research, is a deliberate attempt to damage Wikipedia. There are, of course, more juvenile forms of vandalism, such as adding irrelevant obscenities or crude humor to a page, illegitimately blanking pages, and inserting obvious nonsense into a page. Abusive creation or usage of user accounts and IP addresses may also constitute vandalism.
Vandalism is prohibited. While editors are encouraged to warn and educate vandals, warnings are by no means a prerequisite for blocking a vandal (although administrators usually block only when multiple warnings have been issued).
Even if misguided, willfully against consensus, or disruptive, any good faith effort to improve the encyclopedia is not vandalism. For example, edit warring over how exactly to present encyclopedic content is not vandalism. Careful consideration may be required to differentiate between edits that are beneficial, edits that are detrimental but well-intentioned, and edits that are vandalism. If it is clear that an editor is intending to improve Wikipedia, their edits are not vandalism, even if they violate some core policy of Wikipedia. Mislabeling good faith edits "vandalism" can be harmful, as it makes users less likely to respond to corrective advice or to engage collaboratively during a disagreement. For that reason, avoid using the term "vandalism" unless it is clear the user means to harm Wikipedia; this is even true when warning a user with a user warning template. Choose the template that most closely matches the behavior you are trying to correct.