servile vs soft-soaping

servile

noun
  • A slave; a menial. 

  • An element which forms no part of the original root. 

adj
  • Of or pertaining to a slave. 

  • Not belonging to the original root. 

  • Slavish or submissive. 

  • Not sounded, but serving to lengthen the preceding vowel, like the e in tune. 

soft-soaping

How often have the words servile and soft-soaping occurred in a corpus of books? (source: Google Ngram Viewer )