incoherent vs muddle-headed

incoherent

adj
  • Not making logical sense; not logically connected or consistent. 

  • Not cohering socially, not united. 

muddle-headed

adj
  • Characterized by vague or confused thinking: foolish, dull-witted, semi-conscious. 

How often have the words incoherent and muddle-headed occurred in a corpus of books? (source: Google Ngram Viewer )