Related Clues:

• (Caught) in the act of committing a crime
• Back to old habits
• Having a set-to
• Grinding away
• Vigorously pursuing something
• Persevering, say
• "Look ___ this way . . ."
• Catch someone thus in the act
• Like perennial rivals, constantly
• In a shouting match, perhaps
• Busily engaged
• On task
• Attacking the task
• (Taken) in the act
• A bird is busy