drowsy vs hypnagogic

drowsy

adj
  • Inclined to drowse; heavy with sleepiness 

  • Causing someone to fall sleep or feel sleepy; lulling; soporific. 

  • Dull; stupid. 

  • Boring. 

hypnagogic

adj
  • That induces sleep; soporific, somniferous. 

  • That accompanies falling asleep; especially, pertaining to the semi-conscious period immediately preceding sleep. 

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