Kafkaesque vs unsubstantial

Kafkaesque

adj
  • Marked by a senseless, disorienting, often menacing complexity. 

  • Marked by surreal distortion and often a sense of looming danger. 

  • In the manner of something written by Franz Kafka. 

unsubstantial

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