Definition - What does Rough mean?
Rough is an adjective used for wine which is coarse, or harsh on one's palate. This can be due to an imbalance in the wine, or the age of a wine. A wine which is young, specifically red wine, can have harsh tannins which can be rough and even astringent.
WineFrog explains Rough
High tannin content in a wine is typically the culprit which can make a wine have a rough mouthfeel. It is often unpleasant as the harsh tannin can block the flavor and additional textures of a wine. These tannins may be naturally imparted by oak barrels, staves, oak chips or other oak substitutes like liquid oak. The tannin which is imparted by oak barrels tends to soften over time. So a wine which is described as rough in its youth may become more rounded after even just two years of bottle aging. Tannins which are added by other means, especially by liquid oak, do not change.
While tannins, especially in red wine have the ability to create a rough wine, they act as a natural preservative and when aged properly, add a desired texture to wine.