Related Clues:

• Tied up in knots
• Highstrung
• It can be past or present, in grammar
• Verb form
• Grammar concern
• Like a guitar string
• Like a trampoline's surface
• Far from laid-back
• Form of a verb
• Hardly loose
• Unable to relax
• Stretched to the max
• Like violin strings
• Having no slack
• Grammatical time setter