lament vs plaint

lament

noun
  • An expression of grief, suffering, sadness or regret. 

  • A song expressing grief. 

verb
  • To express grief; to weep or wail; to mourn. 

  • To feel great sorrow or regret; to bewail. 

plaint

noun
  • A complaint. 

  • An accusation. 

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