contend vs defend

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. 

defend

verb
  • To support by words or writing; to vindicate, talk in favour of. 

  • To focus one's energies and talents on preventing opponents from scoring, as opposed to focusing on scoring. 

  • To attempt to retain a title, or attempt to reach the same stage in a competition as one did in the previous edition of that competition. 

  • To call a raise from the big blind. 

  • To ward off attacks against; to fight to protect; to guard. 

  • To make legal defence of; to represent (the accused). 

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