Definition - What does Moldy mean?
Moldy is a wine term that can be used in a couple of ways. A moldy wine is a wine that was made with rotten grapes affected by rot and mold. The finished wine will have an off-odor and/or taste of mold.
Moldy is also used to describe grapes which have mold on them. In this sense, the grapes are "moldy."
WineFrog explains Moldy
It is more likely to have a moldy red wine rather than a moldy white wine. Most molds that form on white grapes, such as noble rot (botrytis cinerea), give desirable characteristics to the wine.
A moldy wine does not always get such a character from being made from rotten grapes. This can happen if an aging vat contains or grows mold during the aging process. A wine can also become moldy from a faulty cork or due to improper storage where there is high humidity. A moldy cork can taint a wine to have such character as well. This is sometimes called a corked wine.