I collect lotsa stuff:
Vintage parts and cars
Automobilia
Trading cards
Watches
Antique toys

So lotsa experience here across a wide range of collectibles.

In modern times, MINT means 'caveat emptor', especially when in ALL CAPS. It's like the used car salesman's "cherry" of decades past.

Cynically, there is no way to define it because the liberty given to the seller to go over the top in their online description is tremendous. Since the seller isn't looking you in the eye across a counter, the use of the word in an internet ad is a sign of someone stretching the truth.

The word can net the unwary or overly trusting and hints at desperation on a seller's part.

I am in no way commenting on the recent sour transaction discussed earlier, and I have no affiliation with either party

: In the pocket watch world we have ongoing discussions (fights)
: about watch grading terms. Here in the wrist watch world, I have
: always been amazed how easily the terms "NOS" (New Old
: Stock) and "MINT" are thrown around. To me NOS means
: that a watch is in its original packaging with all of its
: originally included papers, tags and trinkets and has no
: evidence of ever having been worn. Mint means that the watch is
: in the same unused condition as NOS but does not have all of its
: original packaging etc. To me there is no room for any hedging
: with these terms. It means the watch is NEW...as it would have
: been in a dealer's display case before having been purchased.
: These are terms reserved for very very few vintage or antique
: watches indeed.

: What do you think?

: JohnCote