Faint-hearted
Part of speech: adjective
Definition: Lacking courage; timid
Fearful
Part of speech: adjective
Definition: frighteningfrightened, filled with terrorterrible
Example sentence: A lot of people live in fear because they haven't figured out how you're going to react when faced with a certain set of circumstances. I've come to terms with this by looking deeply into whatever makes me fearful - what are the key elements that get the hairs up on the back of my neck - and then figuring out what I can do about it.