There is of course the alternative grading system used by some sellers.
Guide to Definitions and Translations Relating to Firearms....
Mint Condition: Original condition from the Manufacturer, with all markings present
Minty Condition: As above, with the exception of some deep pitting.
Action Needs Tuning: Missing major parts or worn beyond recognition, will never function correctly.
A Little Rough: Vaguely resembles a firearm.
Good For It's Age: NRA poor to terrible.
$350 Value for $250: Now only twice what it's worth.
Very Old: Assembled in the Orient before 1980.
Much Original Finish:In the deeper crevices.
Some Original Finish: Under the grips.
Shows Honest Wear: Used as a gardening tool by someone.
Very Good Bore: Traces of rifling among the pits.
Good Bore: Pits form a spiral.
Fair Bore: You can see light through it.
Poor Bore: You can't see light through it.
Needs A Little TLC: Beyond hope.
Tight: Acraglas is an amazing compound ain't it?
Hairline Crack: Should be just Airline crack, you can see a jet through it.
Small Chip Out Of Stock: Enough wood missing to be classified as a youth stock.
Nice Patina: Generally covered in rust.
Some Wood Repair: All of the wood has been replaced.
Representative Piece: Still resembles a firearm.
Good Shooter: For those who want to commit suicide.
Pre-War: Before World War II, not the Gulf War.
Naval Variation: Came from a San Diego or Norfolk pawn shop.
Finish Worn: All markings obliterated.
Needs Tightening: All parts worn out.
Some Parts Replaced: Some may be original.
Arsenal Refinished: Refinished in someone's basement.
All Numbers Match: They didn't, but they do now.
Reasonable Offers Considered: I'd love to dump this piece of scrap iron onto someone else.