relentless vs submissive

relentless

adj

  • Unrelenting or unyielding in severity. 

  • Unremitting, steady and persistent. 

submissive

adj

  • Meekly obedient or passive. 

noun

  • One who submits. 

  • One who submits to a dominant partner in BDSM practices. 

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