Related Clues:

• Engine driver, once
• Boo accompanier
• Theater jeer
• Sandblaster's need
• Boo companion
• Moccasin sound
• Sign of an escape?
• ''Boo!'' accompanier
• Emulate a snake
• Fix sans fat
• Prepare cauliflower, say
• Tire leak sound
• Sound issued with an arched back, perhaps
• Let off a little steam
• Rile (up)