Possible Clues:

• Rounded on edge without getting singular, in short
• Prying, on return inform on
• Seems there's nothing vocal to keep one all on edge
• Smelling out around the edge?
• Refusal to turn informer, however inquisitive
• Moulding edge; prying
• Not making much progress prying
• Sniffily prying?
• Being only in the plural, it has one all on edge
• One is all on edge when there's no start for 2 down