@ndpi It's based on the US idiom "to throw a monkey wrench into..." which means to sabotage something. The term "monkeywrenching" was coined by Edward Abbey (from the book Monkeywrench Gang) and its come to mean, besides sabotage and damage to machines, any sabotage, activism, law-making, or law-breaking to preserve wilderness, wild spaces and ecosystems. So a monkeywrencher is one who practices this :>.