Definitions of flimsy:

• noun:   a thin strong light-weight translucent paper used especially for making carbon copies
• adjective:   having little substance or significance

  Example: "A flimsy excuse"

• adjective:   lacking solidity or strength

  Example: "A flimsy table"

• adjective:   very thin and insubstantial

  Example: "Flimsy voile"

• adjective:   resembling cardboard especially in flimsiness