Exothermic (adjective)
That releases energy in the form of heat.
Exothermic (adjective)
That releases heat during its formation, and absorbs it during its decomposition
Exothermic (adjective)
Of an animal: whose body temperature is regulated by external factors; cold-blooded.
Endothermic (adjective)
Of a chemical reaction that absorbs heat energy from its surroundings.
Endothermic (adjective)
Of an animal whose body temperature is regulated by internal factors.
Wiktionary