left field vs surety

left field

noun
  • An unusual or unexpected position, or a viewpoint held by very few others in contrast to the majority viewpoint (especially in the phrases out in left field and way out in left field) 

  • An unexpected, bizarre, or unwatched source (especially in the phrases out of left field and from left field). 

  • The part of a baseball field which is beyond the infield and to the left of a person standing on home plate and facing the pitcher. 

  • The defensive position in the outfield to the left. 

surety

noun
  • A promise to pay a sum of money in the event that another person fails to fulfill an obligation. 

  • One who undertakes to pay money or perform other acts in the event that his principal fails therein. 

  • A substitute; a hostage. 

  • Evidence; confirmation; warrant. 

  • Certainty. 

  • That which makes sure; that which confirms; ground of confidence or security. 

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