There is no grading scale here. There is a state, an amount and a set of dates, and all three go in the listing.
The state
Sealed — unopened, seal intact and shown. Opened, unused — the seal is broken but the product has not been used. Say how you know. Used — say when it was opened and how much is left as a percentage. Tester or sample — said plainly, with the size.
The amount
A percentage, estimated honestly, and a photograph that shows it where the container allows. "About 70% left" with a picture is a description. "Barely used" is a hope.
The dates
Expiry or best-before, where printed. Batch code, shown. The open-jar symbol — the jar with a number and an M, which is how long the product is meant to last once opened.
Where a date has rubbed off or was never printed, say so rather than leaving a gap.
Packaging condition
Carton present or not, dents, crushing, a damaged pump, a cracked lid, a missing applicator, label damage. The carton matters here more than in most categories, because the codes and dates are on it.
What does not belong in a condition description
Any claim that the product treats, cures or prevents something. Describe what it is, what state it is in, and leave the rest to the buyer. Why trust is the product.
Questions people ask
How do I estimate what is left?
Hold it against the light where you can, or weigh it against a full one. Say that it is an estimate.
Is a dented carton a problem?
Only if undeclared. Show it and it is a fact.
Can I sell a tester?
Where it is yours to sell and clearly described as a tester, with the size.
More: condition words across every category, buying beauty products.