monkey wrench vs vicissitude

monkey wrench

noun
  • An unexpected or troublesome problem, obstacle or dilemma. 

  • A wrench (spanner) with an adjustable jaw. 

vicissitude

noun
  • A change, especially in one's life or fortunes. 

  • Regular change or succession from one thing to another, or one part of a cycle to the next; alternation; mutual succession; interchange. 

How often have the words monkey wrench and vicissitude occurred in a corpus of books? (source: Google Ngram Viewer )