A more thorough explanation:

An objectant is a person who contests the validity of a legal document or challenges the placement of a trademark on the Principal Register. They are also known as contestants or caveators.

• If someone believes that a will or trust is not valid, they can become an objectant and contest it in court.
• In trademark law, an objectant can challenge the placement of a trademark on the Principal Register in an interference proceeding, opposition proceeding, or cancellation proceeding.
• In patent law, an objectant is a party to an interference proceeding in the U.S. Patent and Trademark Office.

These examples illustrate how an objectant can challenge the validity of a legal document or the placement of a trademark on the Principal Register. They have the right to contest these matters in court or in legal proceedings.