contend vs interfere

contend

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

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

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

interfere

verb
  • To get involved or involve oneself, causing disturbance. 

  • To sexually molest, especially of a child. 

  • (of waves) To be correlated with each other when overlapped or superposed. 

  • To strike one foot against the opposite foot or ankle in using the legs. 

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