Related Clues:

• It may be hard to break
• Sister's outfit
• Monk's robe
• Established practice
• It's tough to break one
• Riding costume
• Convent wear
• Nail-biting, perhaps
• Regular tendency
• Convent attire
• Gum chewing, for some
• Tough thing to kick
• Religious costume
• Dominant tendency
• Usual practice