contend vs vow

contend

verb
  • To believe (something is reasonable) and argue (for it); to advocate. 

  • To be in opposition; to contest; to dispute; to vie; to quarrel; to fight. 

  • To be in debate; to engage in discussion; to dispute; to argue. 

  • To struggle or exert oneself to obtain or retain possession of, or to defend. 

  • contend with: To try to cope with a difficulty or problem. 

vow

verb
  • To make a vow regarding (something). 

  • To declare publicly that one has made a vow, usually to show one's determination or to announce an act of retaliation. 

  • To make a vow; to promise. 

noun
  • A solemn promise to perform some act, or behave in a specified manner, especially a promise to live and act in accordance with the rules of a religious order. 

  • A declaration or assertion. 

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