Related Clues:

• Unlikely to sag
• Nervous -- and imperfect, perhaps?
• React to a sudden noise
• Under emotional strain in past perhaps?
• Some characters arm riflemen retiring from company
• Company unlikely to collapse
• Feeling edgy
• Moving one's knee a lot, maybe
• Past, present, or future
• Fill out form on both sides taking a hard line
• Company of Irishmen starting manoeuvres
• Anxiety-filled
• Definitely not soft
• Rooted to tree on motorway
• Stable is unlikely to make a move as it's not yielding