sublet vs underlet

sublet

noun
  • Synonym of sublease. 

verb
  • To grant a sublease out of property held under a lease. 

underlet

noun
  • Synonym of sublease. 

verb
  • Synonym of sublet. 

  • To let below the value. 

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