From ward + mate.
wardmate (plural wardmates)
- A patient in the same ward of a hospital
2002, Gregory J. W. Urwin, Facing Fearful Odds: The Siege of Wake Island[1], →ISBN, page 290:Turning to cheer a worried wardmate, Kennedy announced they had nothing to fear — only to change his mind an instant later when bullets started coming through the ceiling.
2010, Houston Gwynne Jones, The Sonarman's War: A Memoir of Submarine Chasing and Mine Sweeping in World War II[2], →ISBN, page 94:...in remembrance of hospital wardmate Joe Johnson, who gave me, if not a change in identity, a new name.