A coward is someone who’s afraid of doing something daring or dangerous. Skydiving might sound exciting in theory, but you might be a coward when it comes to actually jumping out of a plane. Which is probably wise.
Coward comes from the Latin word couda, meaning “tail.” Have you ever seen a scared puppy with its tail between its legs? That’s what people who are cowards would be doing if they had tails. Being afraid of something dangerous might make someone a coward, but the word can also describe someone who avoids doing something difficult or unpleasant. If your boss makes his assistant deliver the unpleasant news about layoffs, you might call him a coward.