adverse vs unfavourable

adverse

adj
  • Unfavorable; antagonistic in purpose or effect; hostile; actively opposing one's interests or wishes; contrary to one's welfare; acting against; working in an opposing direction. 

  • Opposed; contrary; opposing one's interests or desire. 

  • Opposite; confronting. 

unfavourable

adj
  • Serving to hinder or oppose; adverse, disadvantageous, inconducive, unsuitable. 

  • Of wind or weather: causing delay or obstacles; not conducive to travel or work; inclement. 

  • Of a belief, state of mind, etc.: not favourable; disapproving. 

  • Not auspicious; ill-boding. 

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