Corpul are nevoie de apă.

Because corpul means the body, while corp means body in a more general or indefinite sense.

Romanian usually puts the definite article at the end of the noun instead of using a separate word like English the:

• corp = body
• corpul = the body

So Corpul are nevoie de apă literally starts with The body...

Corp is a neuter noun in Romanian.

Romanian neuter nouns behave:

• like masculine in the singular
• like feminine in the plural

In this sentence, the noun is singular, so it takes the singular definite ending -ul:

• corp → corpul

So yes, the gender matters because it affects how the noun is formed.

Are is the 3rd person singular form of the verb a avea, meaning to have.

Since corpul is singular and means the body, the verb must also be singular:

• eu am = I have
• tu ai = you have
• el/ea are = he/she/it has

So:

• Corpul are... = The body has...

Romanian commonly expresses to need with the fixed expression a avea nevoie de, which literally means to have need of.

So:

• are nevoie de apă = needs water
• literally: has need of water

Romanian does have more formal or specific verbs such as a necesita, but a avea nevoie de is extremely common and natural in everyday language.

Nevoie is a noun meaning need.

In the expression a avea nevoie de, it works as part of a set phrase:

• a avea = to have
• nevoie = need
• de = of / for

So the whole structure means to need.

You should learn are nevoie de as one useful chunk, not as separate words only.

Because the expression is a avea nevoie de ceva = to need something.

So the preposition de is required in this structure:

• am nevoie de apă = I need water
• ai nevoie de ajutor = you need help
• corpul are nevoie de apă = the body needs water

You would not normally say Corpul are nevoie apă.

Because apă here means water in a general sense, not the water.

Compare:

• apă = water
• apa = the water

After are nevoie de, Romanian usually uses the noun without the definite article when speaking generally:

• are nevoie de apă = needs water
• are nevoie de somn = needs sleep
• are nevoie de odihnă = needs rest

If you said de apa, that would usually mean of the water or the water specifically, which is less general and would depend on context.

Yes, that is the literal structure.

Word by word:

• Corpul = the body
• are = has
• nevoie = need
• de apă = of water / for water

But in natural English, you would usually translate it as The body needs water.

Because Romanian often does not use subject pronouns when the verb already makes the subject clear.

The verb form are already tells you it is he/she/it has, so a pronoun is usually unnecessary.

You could say:

• El are nevoie de apă = He needs water

But in your sentence, corpul is already the subject, so adding a pronoun would be unnecessary.

Yes, Romanian word order is somewhat flexible, but Corpul are nevoie de apă is the most neutral and natural order.

You may also hear other orders for emphasis, such as:

• De apă are nevoie corpul.

That puts extra focus on water.

Still, for a learner, the safest standard pattern is:

• Subject + verb + expression + object
• Corpul are nevoie de apă.

A simple learner-friendly pronunciation is:

• Corpul ≈ KOR-pool
• are ≈ AH-reh
• nevoie ≈ neh-VOH-yeh
• apă ≈ AH-puh

Full sentence:

• Corpul are nevoie de apă ≈ KOR-pool AH-reh neh-VOH-yeh deh AH-puh

A key sound here is ă, as in apă. It is a short central vowel, something like the a in English sofa.

Yes, you could, but corp and trup are not always identical in tone.

• corp often sounds more neutral, anatomical, or scientific
• trup can sound more physical, literary, or expressive

So Corpul are nevoie de apă is a very natural, neutral sentence, especially in health or biology contexts.