cerebrate vs surmise

cerebrate

verb
  • To think or cogitate, especially so as to make inferences or decisions or to solve problems. 

surmise

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

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

  • Reflection; thought; posit. 

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