Dryness levels are not to be confused with ripeness categories which depend on the ripeness of the grapes harvested in the vineyard.
Whether a wine is dry or sweet can be indicated on the label.
Trocken indicates dry wine without perceptible residual sweetness. It never contains more than 9 grams of residual sugar per liter and often less. It is very dry.
Halbtrocken wines are semi-dry and may not have more than 18 grams of residual sugar per liter. With this barely perceptible sweetness, halbtrocken wines are considered “dry” by most wine lovers.
If none of the above dryness levels can be found on the label the wine is most likely a sweeter style wine, but it can range from off-dry to fully sweet. Generally one can say, the lower the alcohol, the higher might be the residual sugar and often, the residual sugar or perceivable sweetness in the wine does correlate with the ripeness levels.
Trocken (very dry)
Bone-dry sipping wine or aperitif; great with fish/shellfish dishes and light flavored dishes with high acidity (i.e. Lemon)
Multipurpose wine, dry sipping wine or aperitif; great with light to medium flavored dishes; wonderful party wines; very versatile
Off dry or fruity
Wine with some hint of sweetness; great summer sipper; or with vinaigrette salads, lightly spicy dishes and dishes with light cream sauces
Rich sipping wine with noticable sweetness; good with spicy food or dishes that have a fruit component (steak with baked banana, toast hawaii, etc.)
Rich, full sweet wine that can be used for aperitif or as dessert (BA, TBA, Eiswein and some Auslese); wonderful complexity that do not need any company