Argumentative is an evidentiary objection raised in response to a question which prompts a witness to draw inferences from facts of the case.
One common misconception is that often, argumentative questions are meant only to cause a witness to argue with the examiner. This is incorrect. Instead, it is an objection that may be raised when the lawyer himself is making a legal argument. For example, if a lawyer on direct examination were to ask his witness, "So he was driving negligently?," opposing counsel could raise an argumentative objection. This is because negligence is a legal term of art, and the witness cannot reasonably answer the question. Since the lawyer is "arguing" his case through the witness, the objection would be sustained, and then stricken from the record.