There's some overlap here with expressions for "shy" and "nervous," but the "scared" file includes such gems as "She wouldn't bite a biscuit" and "She backed out quicker than a crawfish." A saying as as old as the state itself is "He's first cousin to Moses Rose," a reference to the man (also known as Louis Rose) who has long been said to be the only coward who fled the Alamo before the seige.

Yellow suits her.

He's as yellow as mustard, but without the bite.

Scared as a sinner in a cyclone.

Scared as a cat at the dogpound.

If he was melted down, he couldn't be poured into a fight.