whew vs wo

whew

intj
  • An expression of amazement or surprise. 

  • An expressive sound made indicating the release of one's inner tension; the release of breath; an expression of relief. 

verb
  • To whistle with a shrill pipe, like a plover. 

  • To bustle about. 

wo

intj
  • A call to cause a horse to slow down or stop; whoa. 

  • A falconer's call to a hawk. 

noun
  • A wall. 

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