cat's-foot vs second fiddle

cat's-foot

noun
  • Synonym of cat's-paw: a foot of a cat; (figurative, obsolete) a person used unwittingly or through trickery by another. 

  • Synonym of mountain cudweed (Antennaria dioica). 

  • Synonym of ground ivy (Glechoma hederacea). 

second fiddle

noun
  • A sidekick or subordinate, or the role of such a person. 

  • The person playing second fiddle. 

  • A fiddle part in harmony to the first fiddle. 

How often have the words cat's-foot and second fiddle occurred in a corpus of books? (source: Google Ngram Viewer )