When your senior/manager gives you unclear requirements, you

If you're new to the team and you think it's unclear only to you, ask teammates.
If not, always ask the person providing the requirements directly as it could be a communication issue from their end which they might not realize. Teammates might have different interpretations since the requirements are already unclear which can add to confusion and issues later after work is already in progress. You can get the clarity by asking and include your teammates in the process. And always, keep a record in email like MOM or something to avoid later disagreements.