Related Clues:

• Like a high wire
• Like page-turners
• Linguist's subject
• In need of a rubdown
• Cliff-hanging
• Not loosey-goosey
• Like a newly-installed fan belt
• Far from slack
• Needing a massage, say
• With little slack
• Past condition?
• Past, present or future
• Like a drumhead
• Nail-biting
• Suspense-filled