reptilian
词根词缀：
reptile n. 爬行动物
rept 爬 + ile 表物 → 爬着走的东西 → 爬行动物
reptilian adj. 爬虫类的；卑下的
reptil〔e〕爬行动物 + ian …的 → 爬虫类的；卑下的
subreption n. 隐瞒真相
sub 下 + rept 爬 + ion 表名词 →〔真相〕在下面爬 → 隐瞒真相
surreptitious adj. 鬼鬼祟祟的
sur 下 + rept 爬 + itious …的 → 在下面爬 → 鬼鬼祟祟的
数据来源：新东方英语词汇速记大全
相关例句：
It's part of what we call the reptilian core of the brain, associated with wanting, with motivation, with focus and with craving.
腹侧背盖区也是被我们称作爬虫类脑核的部分。它关系到欲求、动机、专注和渴望。
He licked his lips in an unpleasantly reptilian way.
他令人厌恶地舔着他的嘴唇。
Reptilian creature supposed to live in fire.
传说生活在火中的爬虫动物。
So they must have had a reptilian physiology-that is, a typically cold-blooded, slow metabolism.
所以，它们必然也有著爬行类的生理学，也就是典型的「冷血动物」，代谢速率很慢。
The reptilian brain is much like a baby's brain.
爬行动物脑有点像婴儿的大脑。
What they really mean is that they conceded to their primative emotions ( the reptilian brain based) as opposed to the calculations of the rational part of the brain.
真正的含义就是他们让步他们的主要情感（以象爬虫脑为基础）反抗脑的推理部位的算计。