Question

Throw a Monkey Wrench into the Works to interfere with a smoothly running operation; to upset something in progress

Accepted Answer

All the plans for the party were going smoothly until Tricia threw a monkey wrench into the works. In 1856 a tool was invented by a man named Monk and called Monk's wrench. Later the name was changed to monkey wrench. The sliding jaw of the tool reminded people of a monkey, and the nickname stuck. This American saying of the late 1800s presents the image of someone throwing a monkey wrench into machinery that's working perfectly and "gumming up the works" (see page 84).

Idiom	Throw a Monkey Wrench into the Works
Example	All the plans for the party were going smoothly until Tricia threw a monkey wrench into the works.
Meaning	to interfere with a smoothly running operation; to upset something in progress
Origin	In 1856 a tool was invented by a man named Monk and called Monk's wrench. Later the name was changed to monkey wrench. The sliding jaw of the tool reminded people of a monkey, and the nickname stuck. This American saying of the late 1800s presents the image of someone throwing a monkey wrench into machinery that's working perfectly and "gumming up the works" (see page 84).

Monkey Wrench Works Smoothly Tool Throw Plans Party