half-asleep vs soporific

half-asleep

adj

  • Showing signs of being asleep or very sleepy, as not demonstrating full energy or attention. 

soporific

adj

  • Tending to induce sleep. 

  • Boring, dull. 

noun

  • Something boring or dull. 

  • Something inducing sleep, especially a drug. 

How often have the words half-asleep and soporific occurred in a corpus of books? (source: Google Ngram Viewer )