cold-blooded
Americanadjective
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designating or pertaining to animals, as fishes and reptiles, whose blood temperature ranges from the freezing point upward, in accordance with the temperature of the surrounding medium; poikilothermic.
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without emotion or feeling; dispassionate; cruel.
a cold-blooded murder.
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sensitive to cold.
adjective
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having or showing a lack of feeling or pity
a cold-blooded killing
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informal particularly sensitive to cold
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Technical term: poikilothermic. (of all animals except birds and mammals) having a body temperature that varies with that of the surroundings
Other Word Forms
Etymology
Origin of cold-blooded
First recorded in 1585–95
Compare meaning
How does cold-blooded compare to similar and commonly confused words? Explore the most common comparisons:
Explanation
A cold-blooded animal has a body temperature that varies along with the outdoor temperature, and a cold-blooded person is someone who seems to feel no emotions. Your pet lizard may love you, but she's still cold-blooded. During a hot, sunny day, a cold-blooded animal like a snake experiences a rise in body temperature, which it can only moderate by finding a shady spot to hide. When the sun goes down at night, a snake's body temperature falls. Cold-blooded people, on the other hand, regulate their body temperature even when it's chilly outside, like other warm-blooded animals. They're cruel and unfeeling, though. This meaning comes from the old-fashioned belief that blood temperature rises with emotion.
Vocabulary lists containing cold-blooded
Idioms and Expressions, List 3
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Study co-author Alessandro Chiarenza, a paleontologist at University College London, said an internally regulated body temperature could have allowed tyrannosaurs to live in regions where cold-blooded reptiles struggled to survive.
From Science Daily ● Sep. 20, 2026
New analysis techniques developed in recent years have provided strong evidence that theropods like T. rex, velociraptors and other two-legged dinosaurs were endothermic animals like mammals and birds, rather than cold-blooded, or exothermic, like reptiles.
From Los Angeles Times ● Sep. 16, 2026
It is simply a cold-blooded corporate entity that operates on unadulterated self-interest.
From Salon ● Sep. 15, 2026
From the director of ‘Tiger King,’ a new docuseries examines the cold-blooded, illegal trade in lizards and the like in the 1980s and the lives of those who facilitated it.
From The Wall Street Journal ● Aug. 5, 2026
“How fortunate for me that you finally got proof that I’m not a cold-blooded murderer. You know, other than my word. I mean, what reason would you have to trust that?”
From "Insurgent" by Veronica Roth
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Get a wordDefinitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
