ectothermic

adjective

cold-blooded; body temperature entirely determined by environment

Wiktionary

adj

Etymology: Etymology tree English ectotherm Proto-Indo-European *-ikos Proto-Italic *-ikos Latin -icuslbor. Old French -iquebor. Middle English -ik English -ic English ectothermic From ectotherm + -ic.

Of or relating to an ectotherm; having a body temperature that varies depending on the outside temperature.