drop-dead vs superb

drop-dead

adv
  • Absolutely final; being the deadline, especially in relation to a date set out in a contract upon which adverse consequences will flow if the contract has not been fulfilled. 

  • Very impressively or spectacularly. 

superb

adj
  • First-rate; of the highest quality; exceptionally good. 

  • Grand; magnificent; august; stately. 

How often have the words drop-dead and superb occurred in a corpus of books? (source: Google Ngram Viewer )