supposal vs surmise

supposal

noun
  • Something supposed; a supposition, a hypothesis. 

  • The act of supposing; supposition. 

surmise

noun
  • Thought, imagination, or conjecture, which may be based upon feeble or scanty evidence; suspicion; guess. 

  • Reflection; thought; posit. 

verb
  • To imagine or suspect; to conjecture; to posit with contestable premises. 

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