Used in wine tasting to imply that the wine is out of balance towards the tannins. This type of wine is more than just "hard" it is tannic to a fault, and may not soften enough with age to be enjoyable.

Not necessarily a complimentary term. Lacking in acidity and poorly balanced.

A wine with too much alcohol and too little acidity for the fruit and sugar levels.

lacking lightness or liveliness; "heavy humor"; "a leaden conversation"

thickly coloured wine , too high in tannins and alcohol, lacking finesse and acidity

full-bodied, high alcohol, usually implying unbalanced

wine of high alcohol content lacking in acidity.

High in alcohol; usually critical implying inadequate balancing acidity.

Wine lacking in finesse, strong in alcohol and tannins

An odour which is intense, often sweet and balsamic but lacks lift and vibrancy.

Heavy refers to a fragrance that's potent and not vibrant, and is often described as sweet or balsamic.