stumble vs validity

stumble

verb
  • To cause to stumble or trip. 

  • To trip or fall; to walk clumsily. 

  • To make a mistake or have trouble. 

  • To strike or happen (upon a person or thing) without design; to fall or light by chance; with on, upon, or against. 

  • To mislead; to confound; to cause to err or to fall. 

noun
  • An error or blunder. 

  • A fall, trip or substantial misstep. 

  • A clumsy walk. 

validity

noun
  • The genuinity - as distinguished from the efficacity or the regularity - of a sacrament as a result of some formal dispositions being fulfilled. 

  • The state of being valid, authentic or genuine. 

  • State of having legal force. 

  • A quality of a measurement indicating the degree to which the measure reflects the underlying construct, that is, whether it measures what it purports to measure (see reliability). 

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