Drogul este periculos.

In Romanian, the definite article is usually added to the end of the noun.

• drog = drug
• drogul = the drug

So -ul is the masculine/neuter singular definite article here.

This is one of the biggest differences from English. Romanian often does:

• băiat = boy
• băiatul = the boy

not the boy as two separate words.

Drog is a neuter noun in Romanian.

Romanian neuter nouns behave like:

• masculine in the singular
• feminine in the plural

So in the singular you get:

• un drog
• drogul
• periculos

But in the plural:

• două droguri
• drogurile
• periculoase

This matters because articles and adjectives must match the noun’s grammatical pattern.

Because drog is singular and neuter, and neuter nouns use the masculine singular form of the adjective in the singular.

So:

• masculine singular: periculos
• feminine singular: periculoasă
• masculine plural: periculoși
• feminine/neuter plural: periculoase

Since drogul is singular, the correct form is:

• Drogul este periculos.

Este means is.

It is the 3rd person singular form of the verb a fi = to be.

So:

• eu sunt = I am
• tu ești = you are
• el/ea este = he/she is

In this sentence:

• Drogul este periculos.
• The drug is dangerous.

Yes. In everyday Romanian, e is a very common shorter form of este.

So these both mean the same thing:

• Drogul este periculos.
• Drogul e periculos.

Este sounds a bit more formal or careful; e is very common in normal speech.

Because periculos is not directly modifying the noun inside a noun phrase. It is a predicate adjective after the verb to be.

Structure:

• Drogul = subject
• este = verb
• periculos = adjective describing the subject

This is very similar to English:

• The drug is dangerous.

So the adjective comes after este, just as dangerous comes after is in English.

Yes, Romanian word order is somewhat flexible, but the neutral, most natural order here is:

• Drogul este periculos.

A reordered version like:

• Este periculos drogul.

is possible, but it sounds more marked or emphatic, as if highlighting the drug or reacting to context. For a learner, the standard order is the safest choice.

Usually drog strongly suggests an illegal drug or a narcotic, not ordinary medicine.

So:

• drog = drug, narcotic
• medicament = medicine, medication

This is useful because an English speaker might assume drug and drog always match perfectly, but in Romanian medicament is often the better word for something medical or pharmaceutical.

The indefinite version is:

• Un drog este periculos.

That means A drug is dangerous or One drug is dangerous, depending on context.

Compare:

• drog = drug
• un drog = a drug
• drogul = the drug

So the sentence you were given is specifically about the drug, not just any drug.

The plural would be:

• Drogurile sunt periculoase.
• The drugs are dangerous.

Breakdown:

• drogurile = the drugs
• sunt = are
• periculoase = dangerous

Notice how both the noun and adjective change in the plural.

A simple English-friendly approximation is:

DRO-gool ES-teh peh-ree-koo-LOHS

A few helpful notes:

• g is always a hard g here, like in go
• u is like oo in book/food, depending on accent and closeness
• r is rolled or tapped
• the stress is roughly:
  • DRO-gul
  • ES-te
  • pe-ri-ku-LOS

You may also hear este pronounced clearly as two syllables, or the shorter spoken form e.

Yes, absolutely. It is a fully normal, grammatical Romanian sentence.

It has everything needed:

• a subject: Drogul
• a verb: este
• a description: periculos

So it is a standard pattern you can reuse with many other words, for example:

• Filmul este interesant. = The movie is interesting.
• Orașul este mare. = The city is big.
• Câinele este periculos. = The dog is dangerous.