'Man of War' in the Bible

Then answered one of the servants, and said, Behold, I have seen a son of Jesse the Beth-lehemite, that is skillful in playing, and a mighty valiant man, and a man of war, and prudent in matters, and a comely person, and the LORD is with him.

And Saul said to David, Thou art not able to go against this Philistine to fight with him: for thou art but a youth, and he a man of war from his youth.