chicken

(noun) a scared person, a coward

Example Sentences:

A: Are you going to smoke marijuana, or are you chicken?
B: Leave me alone!

I wanted to go bungee jumping, but I am a chicken. At the last second, I couldn’t do it.

The group members were upset, because their classmate was always such a chicken before giving important presentations.

From the Blogs:

Too chicken to buy Tyson

Media:

Similar idioms:

1. chicken out
2. chicken scratch