A substantive objection refers to a challenge raised against the underlying merits of a claim or defense in legal proceedings, as opposed to procedural objections that focus on the manner in which the case is handled. This type of objection can address issues such as the sufficiency of the evidence, the validity of a legal argument, or whether the facts presented can support a legal remedy. Understanding substantive objections is key when evaluating the strengths and weaknesses of a case during litigation.