'Man of War' in the Bible

Then one of the young men answered, and said, "Behold, I have seen a son of Jesse the Bethlehemite, who is skillful in playing, a mighty man of valor, a man of war, prudent in speech, and a comely person; and the LORD is with him."

Saul said to David, "You are not able to go against this Philistine to fight with him; for you are but a youth, and he a man of war from his youth."