A clause that is not intended to be reused outside the document/binder in which it is contained. In other words, a clause that is so specific that it has little usefulness outside the specific document/binder in which it is inserted.
Unlike a library clause, an ad-hoc clause cannot be searched on, and is not directly visible inside the file browser, because it is stored inside its document/binder. (Advanced users can, however, dig into a document/binder to reveal the internal structure and the ad-hoc clauses.)
A special mode in which clauses may get replaced by shorter versions of themselves, or even left out. Typically, these shorter versions will also be written without any “legalese”, so as to increase the readability for business users who are not legally trained.
For example, in a company’s standard sales agreement, the reporting mode can be used to leave out standard clauses, or replace them with a short title and “company standard clause about … “. This way, when business users (including, in particular, executive management) would have to review a contract that was modified after negotiations with a customer, they will not be distracted by the standard clauses that were left untouched.