plasterless
/ˈplɑːstələs/ /ˈplastələs/adjective
Of a building, structure, etc.: not plastered; without plaster. Also occasionally: not wearing a plaster cast.
Origin
Mid 19th century; earliest use found in ‘Mark Twain’ (1835–1910), author and lecturer (real name Samuel Langhorne Clemens). From plaster + -less.