conundrum /kə-nunˈdrəm/

1. A riddle, esp one whose answer is a play on words
2. Any puzzling question

• buttress-root
• buttress-roots
• buttress-thread
• buttress-threads
• butts
• butt-shaft
• butt-shafts
• butt-ugly
• butt welding
• butty
• butty-collier
• butty-colliers
• butty-gang
• butty-gangs
• buttyman
• butut
• bututs
• but what
• butyl
• butyl alcohol
• butylene
• butylenes
• butyl rubber
• butyls
• butyraceous