Related Clues:

• Unable to sit still
• Like a tie game in overtime
• Awestricken
• Suspenseful
• Not easy
• All atwitter
• Under tension
• Future perfect, for one
• More than uptight
• Head over heels
• In an excited state
• Pluperfect, e.g.
• Apt to snap
• Pulled tight
• Tight, as a drum skin