Related Clues:

• Letters akin to P.D.Q.
• 'Stat'
• In very short order
• Express letters?
• ''... and make it fast!''
• 'Stat' in memos
• 'Yesterday!'
• Order request
• 'Quick!'
• Pronto!
• "On the double!"
• "At once!"
• Order heading
• Initials for the impatient
• Promptness prompter