follow up vs vet

follow up

verb
  • To take further actions remaining after an event; to continue, revisit, or persist; especially, to maintain communication or verify. 

vet

verb
  • To thoroughly check or investigate particularly with regard to providing formal approval. 

noun
  • A veteran (a former soldier or other member of armed forces). 

  • A veterinarian or veterinary surgeon. 

How often have the words follow up and vet occurred in a corpus of books? (source: Google Ngram Viewer )