cold-blooded
UK: /ˌkəʊld ˈblʌdɪd/ | US: /ˌkoʊld ˈblʌdɪd/
adj. 1. (of animals) having a body temperature that varies with the environment; ectothermic.
adj. 2. (of a person or behavior) lacking emotion or empathy; cruel or calculating.
The term "cold-blooded" originated in the 17th century, combining "cold" (from Old English cald, meaning "low temperature") and "blood" (from Old English blōd, symbolizing life or vitality). The suffix "-ed" turns it into an adjective. Initially used to describe reptiles and amphibians (whose body temperature depends on the environment), it later metaphorically extended to describe unemotional or ruthless human behavior, drawing a parallel between physiological and emotional "coldness."
Snakes are cold-blooded creatures that rely on sunlight to regulate their body temperature.
The villain's cold-blooded murder shocked the entire town.
Unlike mammals, most fish are cold-blooded.
Her cold-blooded decision to fire employees before the holidays was widely criticized.
The detective was known for his cold-blooded approach to solving crimes.