Related Clues:

• Sudden swell
• Use a parachute
• Rise rapidly
• Onrush
• Hurdle
• Kind of protector
• Toss-up on a court
• React to a 'boo!'
• Sudden flow, as of water
• Something users protect against
• Sudden voltage increase
• Rise suddenly
• Troop ___
• Billow
• Increase in troop levels