Related Clues:

• Feuding
• Persisting
• Having one's nose to the grindstone
• Keep -- (persist)
• Locking horns
• Fighting, often with 'again'
• Up to no good
• Keep ___ (persist)
• Not getting along
• Go ___ (tussle)
• In a row
• Keep __ (persist)
• Take a crack __ (try)
• Sparring
• Contradictory