It means he claimed service in some unknown command, but there's nothing to substantiate his claim.

I did locate John R. W. Lannom's service file with Co. "B", 11th Tennessee Cavalry. He was captured at Cathey Creek in northeast Tennesse, Dec. 22, 1863, and sent to Rock Island, an unpleasant place if there ever was one. In March 1865 he petitioned prison authorities to take the oath of allegiance, claimed to be against secession &c. That disqualifies him in the eyes of a pension board and others.