Der Mann ist schlank.

Der Mann means the man, while ein Mann means a man.

German uses articles much like English:

• der = the for a masculine noun in the nominative singular
• ein = a / an for a masculine noun in the nominative singular

So:

• Der Mann ist schlank. = The man is slim.
• Ein Mann ist schlank. = A man is slim.

Because Mann is a masculine noun, and here it is the subject of the sentence. In German, the subject is usually in the nominative case.

For a masculine noun in the nominative singular, the definite article is der.

Compare:

• der Mann = the man
• die Frau = the woman
• das Kind = the child

So der tells you both:

1. the noun is masculine
2. it is in the nominative here

In German, all nouns are capitalized, not just names or words at the beginning of a sentence.

So:

• der Mann
• die Frau
• das Haus

This is one of the big visual differences between German and English.

Ist is the third-person singular form of the verb sein (to be).

The subject is der Mann = he / the man, so German uses:

• ich bin = I am
• du bist = you are
• er/sie/es ist = he/she/it is

That is why:

• Der Mann ist schlank.

not

• Der Mann bin
• Der Mann bist

Because schlank comes after the verb ist and works as a predicate adjective.

In German, adjectives usually have endings when they come before a noun:

• ein schlanker Mann = a slim man

But when the adjective comes after sein, werden, or bleiben, it normally has no ending:

• Der Mann ist schlank.
• Der Mann wird schlank.
• Der Mann bleibt schlank.

So:

• schlanker Mann = adjective before noun, with ending
• ist schlank = adjective after verb, no ending

Not exactly.

Both can relate to being thin, but they often feel a little different:

• schlank = slim, often neutral or positive
• dünn = thin, which can be neutral, but sometimes sounds more physical or less flattering depending on context

So:

• Der Mann ist schlank. often suggests he has a slim build.
• Der Mann ist dünn. can simply mean he is thin, but may sound more like a physical condition.

Learners often translate both as thin, but schlank is usually the better word for slim.

Yes, you can. It is grammatically correct.

The difference is mainly in nuance:

• schlank = slim, lean
• dünn = thin

So if you want a more positive or neutral description of body shape, schlank is often better.

The basic word order is:

subject + verb + adjective/complement

So:

• Der Mann = subject
• ist = verb
• schlank = complement/predicate adjective

German main clauses usually place the finite verb in second position. Here, the subject comes first, so the verb follows it.

That makes Der Mann ist schlank. a very standard German sentence pattern.

Yes, but it is marked and less neutral.

German allows different elements to come first, as long as the conjugated verb stays in the second position:

• Der Mann ist schlank. = neutral/default
• Schlank ist der Mann. = unusual, more emphatic or literary

A learner should usually stick with:

• Der Mann ist schlank.

The plural is:

Die Männer sind schlank.

Changes:

• der Mann → die Männer
• ist → sind

So:

• singular: Der Mann ist schlank.
• plural: Die Männer sind schlank.

Notice that schlank still does not take an ending after sind.

That would be:

ein schlanker Mann

Here the adjective comes before the noun, so it needs an ending:

• ein = a
• schlanker = slim
• Mann = man

Compare:

• Der Mann ist schlank. = The man is slim.
• Ein schlanker Mann = a slim man.

This is a very important German difference:

• adjective before noun → usually gets an ending
• adjective after sein → no ending

A rough English-friendly guide is:

shlahnk

A few points:

• sch sounds like English sh
• a is more like the a in father than the a in cat
• the word ends with a clear nk sound

So the full sentence is roughly: dare mahn ist shlahnk

That is only an approximation, but it helps as a starting point.

Yes. They are closely related words and have the same basic meaning.

But watch the pronunciation:

• English man has a short a sound
• German Mann sounds more like mahn to English ears

Also remember the plural is different:

• English: man / men
• German: Mann / Männer

Normally schlank describes physical build, not personality.

So Der Mann ist schlank is understood as describing the man’s body: he is slim/lean.

If you want to describe personality, German would use other adjectives, such as:

• nett = nice
• ruhig = calm
• freundlich = friendly

So schlank is mainly about appearance.