Longman Dictionary of Contemporary English
stone dead
adjective
EXAMPLES FROM CORPUS
▪ His interest in humanity now was stone dead, and probably had been for some time.
▪ Indeed, as expectations can kill the magic stone dead, such occasions are often evoked by going somewhere completely new.
▪ Many of the Witch King's coven fell stone dead.
▪ The face was frozen now, and the rest of the body was stone dead.
Wiktionary
stone dead
a. (context idiomatic English) Utterly dead. alt. (context idiomatic English) Utterly dead.
Usage examples of "stone dead".
Later in the afternoon he fired one more jato unit, leaving the Stone dead in space relative to City Hall and less than an eighth of a mile from it He turned to the phone and called the Mayor.