Related Clues:

• Engaged in sibling rivalry, say
• Keep ___ (persevere) (2 words)
• Busily working (2 words)
• Battling big-time
• Keep __ (be persistent)
• Words with "keep"
• Like Iraq and Iran, in the 1980s
• Engaged in country-to-country combat
• Keep __: persist
• 'They're __ again!'
• Locking horns (2 words)
• Fighting like cats and dogs
• Having a shouting match, say
• Going ___ (arguing)
• Hard ___ (toiling away)