knock the bottom out of

Idioms and Phrases

Also, knock the props out from under . Render invalid, undermine. For example, The discovery of another planet that might support life knocks the bottom out of many theories , or Jane's skilled debating knocked the props out from under her opponent . The first expression dates from the late 1800s, the variant from the first half of the 1900s.

Related Words

• erode
• frustrate
• hurt
• impair
• ruin
• sabotage
• sap
• subvert
• threaten
• thwart
• torpedo
• undercut
• weaken
• wreck