immovable vs poker face

immovable

noun
  • that which can not be moved; something which is immovable 

adj
  • steadfast in purpose or intention; unalterable, unyielding 

  • not capable of being affected or moved in feeling; impassive 

  • not liable to be removed; permanent in place or tenure; fixed 

  • incapable of being physically moved; fixed 

poker face

noun
  • Any similar expression used to prevent giving away one's motives, feelings, or situation. 

  • An impassive facial expression cultivated to prevent other players from determining whether one's actions in the game are the result of a quality hand, or of bluffing. 

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