Near Mint
Cards from newer sets in Near Mint condition will generally have been opened straight from the booster. Other cards in this condition may show signs of very slight wear from shuffling and may also have, but not restricted to, small nicks, scratches, border wear and wear that is not immediately noticeable when the card is sleeved.
Older cards in this condition may show little or no signs of aging, dirt or possible clouding on foils.
Minor Printing Defects. Lines, minor packaging-related border damage, or other small defects will not affect the grade of the card.
Excellent
Excellent cards usually have a couple of white spots at the corners or around the border. The surface may have minor scratches, that are visible upon closer inspection. However, the card cannot be graded Excellent if the creases are so deep that they are visible upon first sight.
An Excellent card is usually in a condition where it is not quite clear if the card would be considered marked or unmarked if it would be played in a tournament without sleeves.
Light Play
Cards graded as Light Play will show sign of general play, may have tournament stamps, signatures (Artist or Magic: The Gathering related signatures) or moderate manufacture/printing defects.
Cards in this category will NOT have signs of inking, water damage, rips, tears or writing (other than signatures).
Cards in this category are normally legal for tournament use once sleeved.
Played
Cards graded as Played may show any amount of wear, and any type of wear, but will usually still be legal for tournament play once sleeved.
Poor
Cards graded as Poor show significant wear, tampering, damage or other markings not through normal play and may not be legal for tournament use, even when sleeved.