Related Clues:

• Not strong or free from defect - perhaps evidence in court
• Unfit or unreliable
• 24 down?
• It's not safe for it to be silent
• Can't 5 down to what is so shaky, perhaps
• You can't depend on its being so silent, perhaps
• Easy to break the silence if it's like this, perhaps
• There's nothing between sun and dun to make it seem so silent
• Weak conciliators must get a report
• Dodgy
• Not firm, as a foundation
• Fallacious (argument)
• Rotten; bad (argument)
• Unreliable, not well
• Not safe or robust