cold-blooded

Having an unregulated body temperature; ectothermic.

“Dead animals radiate heat,” he said. “When you take one down, you can feel it pouring from the wounds. But not this thing.” / “What does that mean?” she asked. / “Cold-blooded maybe, or colder-blooded than we’re used to.” / “Might explain why the heat sensors have trouble picking them up,” Danielle said.

Lacking emotion or compunction.

Here were aſſembled that great philoſopher Mr. Subtile, the coldeſt-blooded metaphyſician of the age.

No Spaniard is ever put out, although he maddens in a moment at the slightest personal affront, for blood boils without fire, “la sangre hierve sin fuego.” He takes these things coolly, which more phlegmatic, colder-blooded foreigners seldom do.

Of a type of horse: tall and muscular, usually good-natured and suitable for heavy work.

Of an engine or vehicle: difficult to start; runs poorly until warmed up.