Related Clues:

• Falter - stop
• Fester
• Become inactive (and malodorous)
• Become foul from inertia
• Become brackish or sluggish
• Become stale from lack of motion
• Sometimes things grind to this
• Stop moving
• Sentry's imperative
• Stand still! Party animal perhaps is with Etna in a knot
• Stop marching
• 'Stop!,' at a checkpoint
• Checkpoint demand
• "Red light!"
• Cease to flow and become smelly