Pronunciation: (kärd'bôrd", -bōrd"), [key]
a thin, stiff pasteboard, used for signs, boxes, etc.
1. resembling cardboard, esp. in flimsiness: an apartment with cardboard walls.
2. not fully lifelike; shallow; two-dimensional: a play with cardboard characters.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.