cucumber vs legal tender

cucumber

noun
  • A vine in the gourd family, Cucumis sativus. 

  • The edible fruit of this plant, having a green rind and crisp white flesh. 

  • A person who is calm and self-possessed. 

legal tender

noun
  • Any form of currency that by law cannot be refused as payment to extinguish a debt equal to the amount offered. 

How often have the words cucumber and legal tender occurred in a corpus of books? (source: Google Ngram Viewer )