A wine that has not been subjected to clarification by the addition of fining materials (e.g. egg whites, gelatine, diatomaceous earth, dry clay powder, and many others).
Nobody likes cloudy wine, so winemakers sometimes go to great lengths to make their wine crystal clear. During the last stages of production, a wine will “fall bright”, when the majority of grape matter and dead yeast cells drop to the bottom of the tank or barrel. For some wines, this is sufficient to make a crystal clear wine, ready for bottling; others need some help. There are also times when a little problem arises that must be taken care of. Fining is a very old technique that helps rid wine of various unwanted conditions, whether visible, olfactory or tasteable.
Fining materials do their work by attaching to unwanted matter and forcing it to drop out of the wine. The fining materials themselves do not remain in the wine but join the sludge left behind. Fining can be light or aggressive, depending on the material used and the result the winemaker is looking for. A light fining, perhaps with beaten egg whites, is rather standard with red wines. At the other extreme is a wine that went in the wrong direction and then requires a great deal of intervention to salvage it, and there is a long list of options. In either case, fining removes something from the wine, and there are those who believe the wine is the lesser for it -- that fining removes character as easily as it removes other things.
A wine that is unfined has had no extra elements introduced to it. This is reassuring to the vegetarian or vegan who doesn’t want a wine that has had egg, milk, blood, bone, or gelatine in it. Unfined also means that the wine was at its peak without this intervention. The final bonus is that an unfined wine has all the goodness it was born to have – nothing has been removed through fining – and in that case, you are likely to see the word “Unfined” proudly displayed on the bottle label.