Related Clues:

• Like a tuned drumhead
• Nerve-racking
• On the verge of snapping
• Grammar class subject
• Antsy
• Without wrinkles
• Ready to snap
• Stretched to the limits
• Showing strain
• Strung out
• Unloose
• Present, for example
• Language study topic
• Opposite of loose
• Perfect, e.g.