Objector (noun)

1. A person who objects or expresses disapproval or opposition.
2. A person who refuses to comply with a decision or a rule.

Origin:

The word "objector" comes from the verb "object" which means "to express disapproval or opposition" and the suffix "-or" which means "one who does something".

Examples:

1. He was the only objector in the meeting.
2. The objector raised valid points during the discussion.
3. He was an objector to the proposed changes.
4. The objector refused to comply with the new rule.
5. The objector's vote was the deciding factor in the decision.