An adjective before a German noun normally takes an ending. To choose it, inspect the complete noun phrase: its case, gender, number and article word. An adjective used as a description after sein normally stays uninflected. Instead of learning isolated fragments such as guter, keep a full example and change one part at a time. This guide provides a decision method and representative examples; a complete declension table remains useful for checking less familiar combinations.
Why is it der gute Kaffee but guter Kaffee?
In der gute Kaffee, the definite article is followed by a weak adjective form. In article-free guter Kaffee, the adjective has the strong nominative masculine ending. The noun and role are the same; the article context changes. Weak adjective forms use -e or -en, while strong forms have a wider set of endings. This explains the contrast without making gute or guter a permanent property of the adjective gut.
Der gute Kaffee steht auf dem Tisch. Guter Kaffee ist teuer. Both phrases are nominative masculine singular, but the article context differs. Change the article before changing the sentence role.
This example does not mean every adjective after an article ends in -e.
Sources: Starke und schwache Adjektivflexion
Why do adjectives after ein sometimes use different endings?
The ein-pattern contains both endingless and visibly inflected article forms. An adjective after endingless ein can carry a strong form, as in ein guter Kaffee; after einen it takes a weak form, as in einen guten Kaffee. Many teaching grammars call this combination mixed declension. The adjective does not acquire one fixed ending after the word ein: its form still reflects the case, gender and number of the complete phrase.
Ein guter Kaffee hilft mir morgens. Ich bestelle einen guten Kaffee. In the second example, einen and guten belong to the masculine accusative phrase required by this use of bestellen.
Mixed is a teaching label; IDS also explains the pattern through strong and weak forms.
Why is it einige neue Bücher but diese neuen Bücher?
Plural quantity words do not all govern adjectives like a definite or demonstrative article. After einige, the adjective normally keeps strong plural forms: einige neue Bücher, einiger neuer Bücher. After diese, it follows the weak pattern: diese neuen Bücher. Both phrases contain a word before the adjective, so “any preceding word makes the adjective weak” is insufficient. The particular quantity word and construction matter; other quantifiers can show different patterns or variation.
Einige neue Bücher liegen hier. Diese neuen Bücher gehören mir. In these nominative plural phrases, neue and neuen differ because einige and diese have different effects on the following adjective.
The contrast concerns einige and diese in plural phrases; do not extend it to every quantity word or singular form.
Sources: Minimale Nominalphrasen
Why does das neue Fahrrad become das Fahrrad ist neu?
Neue in das neue Fahrrad is an attribute before a noun, so it is inflected. In das Fahrrad ist neu, neu is a predicative description and stays uninflected. The distinction is grammatical function, not the object being described. The same adjective can also be used adverbially without an attributive ending. A nearby article does not automatically give an ending to every adjective elsewhere in the sentence.
Das neue Fahrrad ist leicht. Das Fahrrad ist neu. Neu describes the same object in both examples, but its grammatical position changes. The meaning alone does not determine the ending.
This contrast concerns ordinary adjective use, not every lexicalised or unusual adjective construction.
Sources: Flexion der Adjektive
Can I choose an adjective ending before I know the case?
No: gender alone does not determine an adjective ending. Der kleine Hund, den kleinen Hund and mit dem kleinen Hund involve the same masculine singular noun but different case contexts. You also need to know whether an article word is present and which form it has. The complete noun phrase supplies the relevant information; treating the article, adjective and noun as three unrelated corrections hides the reason for the agreement.
Der kleine Hund schläft. Ich sehe den kleinen Hund. Ich gehe mit dem kleinen Hund. The same noun appears in three roles, and the complete phrases must be checked separately.
Gender alone cannot distinguish all endings; you need the whole phrase and its construction.
Sources: Starke und schwache Adjektivflexion
A comparison to practise
| Situation | Form or meaning | Original example |
|---|---|---|
| Before a noun with definite article | weak pattern | der ruhige Raum |
| After an endingless ein form | strong adjective form | ein ruhiger Raum |
| Plural after einige | strong adjective pattern | einige neue Bücher |
| Ordinary description after sein | no adjective ending | Der Raum ist ruhig. |
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kleines
Fenster is neuter nominative here; endingless ein leaves the adjective with the strong -es form.
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kleine
The neuter accusative phrase has the definite article das; this weak adjective form ends in -e.
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klein
Klein is a predicative description after ist. It does not take the attributive ending used before the noun.
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- Starke und schwache Adjektivflexion — Leibniz-Institut für Deutsche Sprache. Checked 8 October 2026.
- Vertiefung: Gemischte Adjektivflexion — Leibniz-Institut für Deutsche Sprache. Checked 8 October 2026.
- Minimale Nominalphrasen — Leibniz-Institut für Deutsche Sprache. Checked 8 October 2026.
- Flexion der Adjektive — Leibniz-Institut für Deutsche Sprache. Checked 8 October 2026.