Related Clues:

• Put in operation
• ''__ only as directed''
• Participate
• Join the club
• Join, as the Army
• Sign up for a class
• "What's the ___?" (quitter's lament)
• Not squander
• Single-___
• Take a recruiter's offer
• Juice, as an athlete
• "___ only as directed"
• Adopt
• Mileage, in a way
• ___ tax