Green-vinyl.com uses the Goldmine Standard for listing the condition of items for sale:

Mint (M)

Absolutely perfect in every way. Certainly never been played, possibly even still sealed.

Near Mint (NM or M-)

A nearly perfect record. The record shows no obvious signs of wear. A 45 sleeve  doesn't have  more than the most minor defects, such as almost invisible ring wear or other signs of slight handling. No creases, folds, seam splits or other noticeable similar defects. No cut-out holes, either. And of course, the same counts for any other inserts, such as posters, lyric sleeves and the like.

Very Good Plus (VG+)

A Very Good Plus record will show some signs that it was played and otherwise handled by a previous owner who took good care of it. Record surfaces may show some signs of wear and may have slight scuffs or very light scratches that don't affect one's listening experiences. It might have slight warps that do not affect the sound. The label may have some ring wear or discoloration, but it wiil be barely noticeable. The center hole will not have been misshapen by repeated play. Picture sleeves and LP inner sleeves will have some slight wear, lightly turned up corners, or a slight seam split. An LP cover may have slight signs of wear also and may be marred by a cut-out hole, indentation or corner indicating it was taken out of print and sold at a discount. In general, if not for a couple things wrong with it, this would be Near Mint. All but the most mint-crazy collectors will find a Very Good Plus record highly acceptable.

Very Good (VG)

Many of the defects found in a VG+ record will be more pronounced in a VG disc. Surface noise will be evident upon playing, especially in soft passages and during a song's intro and fade, but will not overpower the music otherwise. Groove wear will start to be noticeable, as will light scratches (deep enough to feel with a fingernail) that will affect the sound. Labels may be marred by writing, or have tape or stickers (or their residue) attached. The same will be true of picture sleeves or LP covers. However, it will not have all of these problems at the same time, only two or three of them.

Good (G), Good Plus (G+)

Good does not mean Bad! A record in Good or Good Plus condition can be put onto a turntable and will play through without skipping. But it will have significant surface noise and scratches and visible groove wear (on a styrene record, the groove will be starting to turn white). A cover or sleeve will have seam splits, especially at the bottom or on the spine. Tape, writing, ring wear or other defects will start to overwhelm the object.

Poor (P), Fair (F)

The record is cracked, badly warped, and won't play through without skipping or repeating. The picture sleeve is water damaged, split on all three seams and heavily marred by wear and writing. The LP cover barely keeps the LP inside it. Inner sleeves are fully seam split, crinkled, and written upon.