doot vs think on

doot

verb

  • think 

  • to scan 

  • to tap a card 

  • doubt 

noun

  • doubt 

  • beep (electronically-produced tone) 

think on

verb

  • To think about; to meditate concerning. 

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