fore vs heads up

fore

intj
  • An exclamation yelled to inform players a ball is moving in their direction. 

adv
  • In or towards the bows of a ship. 

  • In the part that precedes or goes first; opposed to aft, after, back, behind, etc. 

noun
  • The front; the forward part of something; the foreground. 

adj
  • Forward; situated towards the front (of something). 

heads up

intj
  • Used as an informal warning, caution, or call for attention; pay attention! 

adj
  • Containing only two players. 

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