There is no numbered scale for clothing, and the words people use are vague enough that the measurements have to do the real work.
The words
New with tags — unworn, tags attached. New without tags — unworn, no tags. Say why if you know. Excellent — worn, no faults worth naming. Good — worn, with faults you have named. Worn — real wear, priced for it.
Each of those should be followed by the specifics. The word alone is an opinion; the specifics are the listing.
Where to look, in order
Collar and cuffs — fraying, discolouration, the inside of the collar especially. Underarms — staining, thinning, deodorant marks. Hems and seams — loose threads, repairs, let-down hems. Elbows and knees — thinning and shine. Buttons and zips — present, matching, working. All-over — pilling, fading, shrinkage, holes.
Say the alterations
Taken in, let out, hemmed, sleeves shortened, buttons replaced. Not faults — facts. They change what the label means.
Smell is a condition
It is the one thing that cannot be photographed and the most common cause of returns in used clothing. Storage, smoke, damp, perfume: say it.
Measurements make the words honest
"Good condition, chest 54cm flat, length 72cm, sleeve 63cm" is a listing nobody can argue with. "Good condition, size L" is a disagreement waiting for a parcel.
Questions people ask
What counts as new without tags?
Unworn. Not "worn once". Worn once is excellent, and say it was worn once.
Do I have to mention a tiny mark?
Yes. Small marks are the ones buyers feel cheated by, because they look hidden on purpose. Naming the flaw raises the price.
How do I describe shrinkage?
By measuring it. That is the whole answer, and it is why measurements come first.
More: condition words across every category, buying menswear.