What does 4A military classification mean during World War 1?

During World War I, the 4A military classification indicated that an individual was unfit for military service due to physical or mental reasons. This classification was part of a broader system used by the U.S. military to categorize potential draftees and assess their eligibility for service. Those classified as 4A were exempt from conscription and military duties, allowing for the identification of those who could serve effectively.