poikilotherm Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition noun. an animal that cannot regulate its body temperature. Example Sentence A crocodile is a poikilotherm. More Example Sentences Fish and reptiles are examples of poikilotherms. Synonyms cold-blooded animal; ectotherm Antonyms endotherm; warm-blooded animal Hear It! Say It! Write It! poikilotherm Switch to cursive Start Share with your friends: