We don't have synonyms for drop-dead yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are drop dead, drop-head and dropdead.
(adv) :
(informal) Very impressively or spectacularly.
(adv) :
(informal, not comparable, business, law) 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.
(adv) :
(informal) Very impressively or spectacularly.
(adv) :
(informal, not comparable, business, law) 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.