Formal:
* Interviewee: This is the most common and neutral term.
* Respondent: This is often used in surveys and research studies.
* Subject: This term is less common and can sometimes sound impersonal.
* Source: This is used when the interviewee is providing information for a news story or article.
Informal:
* The person being interviewed: This is a simple and straightforward option.
* The interview subject: This is similar to "subject" but less formal.
* The interviewee: This is a more colloquial way to say "interviewee."
Other options:
* Guest: If the interview is for a podcast, radio show, or television program.
* Participant: If the interview is part of a larger study or event.
The best term to use will depend on the specific situation and the tone you want to convey.