throw a monkey wrench in(to) (something)(redirected from threw a monkey wrench into)
throw a monkey wrench in(to) (something)
To disrupt, foil, or cause problems to a plan, activity, or project. Primarily heard in US. We had everything in line for the party, but having the caterer cancel on us at the last minute really threw a monkey wrench into our plans! It'll really throw a monkey wrench in the works if the board decides not to increase our funding for this project.
throw a monkey wrench into
Sabotage or frustrate a project or plans, as in The boss threw a monkey wrench into our plans when he said we'd have to work Saturday. This transfer of industrial sabotage-that is, throwing a tool inside machinery-to other subjects dates from the early 1900s.