frou-frou vs improper

frou-frou

adj
  • Unimportant, silly, useless. 

  • Liable to create the sound of rustling cloth, similar to 19th-century dresses. 

  • Highly ornamented, overly elaborate; excessively girly. 

noun
  • A rustling sound, particularly the rustling of a large silk dress. 

verb
  • To move with the sound of rustling dresses. 

improper

adj
  • unsuitable to needs or circumstances; inappropriate; inapt 

  • Not properly named; See, for example, improper fraction 

  • Not in keeping with conventional mores or good manners; indecent or immodest 

  • Not consistent with established facts; incorrect 

  • Of a complex random variable, correlated with its conjugate 

  • Not according to facts; inaccurate or erroneous 

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