Possible Clues:

• 'Sharpen, appetite say (4)'
• Improve, as an edge
• Make keen and hot in feeble surroundings
• Arouse husband during dip
• Edge - the wicket falls
• Sharpen the blade of (a tool/weapon)
• Sharpen, as a blade
• Work on the edge
• Sharpen, appetite or razor
• Stimulate (appetite)