stone cold
Completely bereft of emotion or concern. Hyphenated if used as a modifier before a noun. The criminal was stone cold as she sat in the courtroom stone and heard the verdict being handed down. I just can't understand how such a sweet boy could turn into a stone-cold killer like that.
stone cold
Unfeeling, insensible, as in That sad story left her stone cold. This analogy was already used by Shakespeare in Henry V (2:3): "Cold as any stone."