Related Clues:
- Participate
- Add to the club
- Join the club
- Sign up, as for a class
- Join the student body
- Sign up, variantly
- Register for a class (Var.)
- Join the class
- Register for (with "in")
- Register, as for a course (Var.)
- Loner inclined to join in
- Join up, sing on
- Sign on, register
- Join up, sign on
- Sign on, being a loner