Near Mint: NM cards have never been played and should display no more than 1 or 2 tiny white spots either from storage or production. Not accounting for centering, they should be in gradable condition. If a card has been played once even in double sleeves I will list it as LP.
Unplayed: Similar to NM cards these have never seen a game of magic. However, they may have some minor white spots or a hair thin scratch from storage or production. Depending on the degree of the issues they will be listed as either LP or NM in the description.I sometimes list new cards as LP/Unplayed because modern sets frequently have production lines or scratches straight out of the pack. Lightly Played: Overall LP cards are still in collectible condition. However, they may have a few white spots or light scratches. Deeper scratches, too much surface dirt or more significant damages to the corners/edges are not allowed for LP. Moderately Played: It is visible that MP cards have been played.
However, they should not have any significant damages such as creases. Heavy Play: HP cards look like they have been played without sleeves.