opine vs think straight

opine

verb
  • To have or express an opinion; to state as an opinion; to suppose, consider (that). 

  • To give one's formal opinion (on or upon something). 

noun
  • Any of a class of organic compounds, derived from amino acids, found in some plant tumours 

think straight

verb
  • To think clearly 

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