continual vs inconstant

continual

adj
  • Recurring in steady, rapid succession. 

  • Seemingly continuous; appearing to have no end or interruption. 

  • Forming a continuous series. 

inconstant

adj
  • Not constant; wavering. 

  • Unfaithful to a lover. 

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