hoard vs save for a rainy day

hoard

noun
  • A cache of valuable objects or artefacts; a trove. 

  • A hoarding (temporary structure used during construction). 

  • A hidden supply or fund. 

  • A hoarding (billboard). 

  • A projecting structure (especially of wood) in a fortification, somewhat similar to and later superseded by the brattice. 

verb
  • To amass, usually for one's own private collection. 

save for a rainy day

How often have the words hoard and save for a rainy day occurred in a corpus of books? (source: Google Ngram Viewer )