strident vs unharmonious

strident

noun
  • One of a class of s-like fricatives produced by an airstream directed at the upper teeth. 

adj
  • Grating or obnoxious 

  • Loud; shrill, piercing, high-pitched; rough-sounding 

  • Vigorous; making strides 

unharmonious

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