Deceit is the name for the practice.
Deceit 是指“欺骗”这个品行的名字
例子：He was well practiced in the art of deceit.
Deception is the name for a particular instance of deceit.
Deception 是 Deceit 的一个具体实例,指某一次欺骗行动或行为.
例子：The sale of the moon was an act of deception.