Source : Webster's Revised Unabridged Dictionary (1913)

Skin-deep \Skin"-deep`\, a.
   Not deeper than the skin; hence, superficial. --Lowell.

Source : WordNet®

skin-deep
     adj : involving a surface only; "her beauty is only skin-deep";
           "superficial bruising"; "a surface wound" [syn: {superficial},
            {surface(a)}]