legal representative; legal guardian
A person who gives consent on behalf of another, typically in medical or legal contexts. Often used for a guardian who consents to medical treatment for a minor or incapacitated person.
Consent from a legal guardian is required for surgery on a minor.
When participating in a clinical trial, a legal representative signs the consent form.
法定代理人 is a legal agent or representative under the law, a more formal and comprehensive term than 代諾者, which focuses on the act of giving consent.
Compound of 代 (substitute) + 諾 (consent) + 者 (person). The term is a modern legal coinage.