One of the best descriptions I've read is from Dick Francis, in the person of one of his fictional characters: Fear in the presence of danger is normal. Absence of fear is not. Keeping one's head in spite of fear is courage.

Since I would oppose cowardice and courage, I would claim that a coward is someone who allows their fear (of a real danger) to rule their behavior. This would not apply to a suicide attacker unless you claim that they were afraid to live. I've never understood why something you wouldn't do is considered cowardly.

Meanwhile, what is the word in English for excessively modest in the sense of being really overly protective of the sight of one's body? I thought the word was Prude, but I called an incredibly modest (not in the sense of accomplishment) friend prudish and was told that was terrifically insulting, while all I meant to do was describe his hebavior. What is the descriptive term?