Njezin parfem miriše na cvijeće, dok moj parfem miriše na limun.

These are possessive adjectives:

• njezin = her
• moj = my
• parfem = perfume

In Croatian, possessive words usually agree with the noun in gender, number, and case.

Because parfem is:

• masculine
• singular
• here in the nominative

the forms are:

• njezin parfem
• moj parfem

If the noun changed, the possessive form might change too.

Miriše is the 3rd person singular present tense of mirisati.

So:

• mirišem = I smell / I am smelling
• mirišeš = you smell
• miriše = he/she/it smells

In this sentence, it means gives off a scent or smells like.

So:

• Njezin parfem miriše... = Her perfume smells...

In Croatian, mirisati na + accusative means to smell like / to smell of.

So:

• miriše na cvijeće = smells like flowers
• miriše na limun = smells like lemon

This is just the normal pattern with this meaning. English uses like or of, but Croatian commonly uses na here.

Cvijeće means flowers as a general mass or collective idea, while cvijet means a flower.

So:

• cvijet = a flower
• cvijeće = flowers / floral scent / flower-related fragrance

In a sentence about perfume, cvijeće sounds natural because we usually mean a general floral smell, not the smell of one single flower.

They are in the accusative, because na after mirisati takes the accusative.

So:

• na cvijeće
• na limun

A useful thing to notice is that these forms look the same as the dictionary form:

• cvijeće is a neuter singular noun, and its nominative and accusative singular are the same.
• limun is an inanimate masculine noun, and its nominative and accusative singular are also the same.

So the case changed grammatically, even though the word form did not visibly change.

Here dok means while, whereas, or while on the other hand.

In this sentence, it connects two contrasting ideas:

• Her perfume smells like flowers
• my perfume smells like lemon

So dok is showing contrast, not mainly time.

A natural translation here is:

• ..., whereas my perfume smells like lemon.

No, not necessarily.

You could also say:

• Njezin parfem miriše na cvijeće, dok moj miriše na limun.

That is perfectly natural and means the same thing.

Repeating parfem:

• makes the sentence more balanced
• can sound a little clearer
• puts equal emphasis on both perfumes

Leaving it out is also common because moj clearly stands for my perfume.

Croatian usually does not need an explicit subject pronoun when the subject is already clear.

The verb ending often tells you the person and number, and the noun is already present:

• Njezin parfem miriše...

So Croatian does not need to add a separate word for it. The noun parfem already functions as the subject.

This is normal in Croatian and other Slavic languages.

No. Croatian has more than one possessive form for her, including njezin, and learners may also meet njen.

For standard learning purposes:

• njezin is a very common and fully standard form

So in a textbook-style sentence like this, njezin parfem is exactly what you should expect.

A rough guide:

• njezin ≈ NYEH-zeen
  • nj sounds like the ny in canyon
• cvijeće is harder, roughly ≈ TSVYEH-cheh
  • c = ts
  • vj is a blended sound
  • ć is a soft ch-like sound

You do not need a perfect English equivalent, but the important parts are:

• nj is not pronounced like separate n + j
• c is ts
• ć is softer than English ch

Yes. Depending on context, mirisati can mean:

• to smell pleasant
• to smell like something
• more generally to have a smell/scent

In this sentence, it clearly means:

• to smell like

because it is followed by:

• na cvijeće
• na limun

So the structure tells you the intended meaning.