Possible Clues:

• Protect against challenge or attack
• Justify tip after rising gratified
• Fed up at last with not having an attack of this
• Act as a guard
• Fed up at last not be offensive
• Make a case for three successive letters to finish
• No to be offensive may make one fed up at last
• Compete to retain (sporting title)
• Not to be offensive, fed up at last
• Fed up at last of not being offensive