Final answer:
James means that a faith without good works is not authentic.
Step-by-step explanation:
When James says that those who fail to do good works, or deeds, have a faith that is "dead", he means that their faith is not authentic. He is suggesting that true faith should be accompanied by good works as evidence of a genuine belief. James is emphasizing the importance of demonstrating one's faith through actions, rather than simply professing belief.