forewarning vs taster

forewarning

noun
  • An advance warning; an omen. 

taster

noun
  • A person who is, by genetic makeup, able to taste phenylthiocarbamide 

  • A sample of something bigger or grander intended for future use 

  • Someone who tastes something, especially food, wine etc., for quality. 

  • A kind of zooid situated on the polyp-stem of certain Siphonophorae, resembling the feeding zooids, but destitute of mouths. 

  • An object in which, or by which, food or drink is tasted, for example a dram cup 

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