card·board 
(kärdbôrd′)
(kärdbôrd′)n.
A material similar to thick, stiff paper, that is made of pressed paper pulp or pasted sheets of paper. It is used for making cartons and signs, for example.
adj.
1. Made of or consisting of cardboard.
2.
a. Flimsy; insubstantial.
b. Lacking depth; superficial: a movie with only cardboard caricatures of its historical subjects.