Soap substitute

• Plant used as soap
• Whac-__: arcade game
• Whack-___
• Plant whose roots are used as detergent
• "...mountain out of --- hill"
• Root used as soap in Mexico
• Plant with detergent properties
• Plant used as a cleanser
• Whac- -- (reflex-testing carnival game)

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1831, from Mexican Spanish amole , from Nahuatl (Aztecan) amolli "soap-root."