Excellent: your laptop has no cosmetic damage (e.g. scratches or cracks in plastic parts), marks or signs of wear.
Above Average: your laptop shows minor signs of wear from normal use according to its age. Minor marks or scratches may be present.
Average: your laptop shows signs of moderate use but it keeps its integrity. Signs could be any or a combination of the following: keyboard has shiny buttons; there's a high number of visible marks and scratches; LCD hinges aren't tight and don't hold the screen upright very well.
Below Average: your laptop has suffered some damage. Plastics are scratched up and cracked.
Poor: your laptop has been "abused". It barely holds together. Plastics are scratched up and cracked.