A warrior is literally someone who wages war – a fighter. In the context of spiritual work a warrior is someone who struggles to face things as they really are, whereas a coward is someone all too willing to retreat into their own (or other peoples') thoughts, feelings and opinions about things. The warrior strives to always engage with spirit whereas the coward with ego. Spirit and ego are not complimentary opposites, they are mutually exclusive, they destroy each other. So a warrior is a gleaming spirit, and a coward a selfish ego.