Related Clues:

• Swear
• Swear word
• Codger
• Give a damn?
• Talk a blue streak
• Talk a blue streak?
• Emulate a sailor
• Stubborn sort
• With 4-Down, upbraid in no uncertain terms
• Use four-letter words
• Turn the air blue
• Say '%@&#!'
• Spit four-letter words
• Blaspheme
• Use profanity