stone-cold

/S T OW1 N K OW0 L D/
adjective
  1. 1

    Completely cold.

    โ€œBy the time I returned to my desk, my tea was stone-cold.โ€

  2. 2

    Without emotion.

    โ€œHe was a stone-cold killer: he didn't flinch as he took the shot.โ€

Source: https://en.wiktionary.org/wiki/stone-cold