a nuisance, something that ditracts from getting things done. This is a variation on "a monkeywrench in the works" which dates back to the industrial revolution. If a wrench were to fall into the gears of the large factory machine, it would make everything stop.

monkey in the wrench was first used in the movie Die Hard in 1988. In the film, the hero is a cop trapped in a highrise building full of terrorists. After killing several of them, he talks to their leader via a cb radio. When the villain asks who he is, he states,
"Just a fly in the ointment Hans, a monkey in the wrench, a pain in the ass."
by Bobby White June 30, 2008
1. An adjustable wrench.
2. An imaginary tool of sabotage, destruction, overthrow and mischief.
1. Hey would you be so kind and hand me that monkey wrench?
2. Everything was going so well but then you threw a monkey wrench in my plan.
by Mattony February 28, 2014
Fool, gullible person. See Tool.
Quit being such a monkey wrench, Vellius. Chris knew it was you the whole time, you shippler.
by MJK October 8, 2005
To sabotoge or disrupt.
George W. Bush's claim of Iraqi weapons of mass destruction threw a MONKEY WRENCH in Colin Powell's political aspirations.
by Mikail Bevale March 6, 2005
A computer programming term.
To write sloppy and inefficent code that solves the problem instead of a proper solution because you can't get it to work correctly and have run out of time to fix it.
"Man, this code is nasty, but it works. They really monkey-wrenched that function in there."
by Cynamon August 17, 2005
My favorite Foo Fighters song of all time. Great lyrics, great guita, vocals ,and drums all done by the renaissance man Dave Grohl.
What do you do when all your enemies are friends!
by alex k April 16, 2004