cold-blooded          
adjective uk/ˌkəʊldˈblʌd.ɪd/ us/ˌkoʊldˈblʌd.ɪd/
 (动物)冷血的
Cold-blooded animals can only control their body heat by taking in heat from the outside or by being very active.
  Snakes and lizards are cold-blooded animals. 蛇和蜥蜴都是冷血动物。 
 Compare: warm-blooded
  冷酷无情的,残忍的
behaving in a very cruel way with no sympathy for other people
  a cold-blooded murder 残忍的谋杀