a person who is not brave or who does not have the courage to do things that other people do not think are especially difficult 胆小鬼；懦夫；胆怯者
You coward! What are you afraid of?
你这胆小鬼！你怕什么呢？
I’m a real coward when it comes to going to the dentist.
我一去看牙医就胆战心惊。