objection
A strong, spoken disagreement about something being done or said.
An objection is a formal statement of disagreement or disapproval, often made to stop something from happening or to challenge whether something is fair or correct.
You've probably heard lawyers in courtrooms say “Objection, Your Honor!” when they believe the opposing attorney has asked an improper question or broken a rule. The judge then decides whether to sustain the objection (agree with it) or overrule it (reject it). This is objection in its most dramatic form, but the concept shows up everywhere.
In a classroom debate, you might raise an objection to an opponent's argument by pointing out faulty reasoning. At a city council meeting, residents can voice objections to a proposed new ordinance. Even in casual conversation, when your friend claims that vanilla is better than chocolate, your strong disagreement could be called an objection.
When you object to something, you're actively speaking up, making your opposition known, and often trying to prevent something from moving forward. An objection is disagreement that demands to be heard.