Possible Clues:

• Mark made by brush
• An attack of apoplexy
• Such a blow might be the end of you
• Blow for a member of the rowing crew
• Line drawn at even the teeniest bit of work
• Hit one having a row
• Oarsman's line
• A hearty blow with an oar
• Chip or putt
• A row with him may be all too hearty and brainy