undern vs vesper

undern

noun
  • Synonym of evening. 

  • A light meal, particularly in the afternoon. 

  • Synonym of afternoon. 

vesper

noun
  • The evening. 

  • A vesper bat. 

  • A vesper martini. 

  • The bell that summons worshipers to vespers; the vesper-bell 

adj
  • Evening. 

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