A jante está limpa.

In Portuguese, a can be the feminine singular definite article, so here it means the.

• a = the (feminine singular)
• uma = a / an (feminine singular, indefinite)

So:

• A jante = the rim
• Uma jante = a rim

Because jante is a feminine noun, it takes a.

Because nouns in Portuguese have grammatical gender. This does not always have anything to do with real-world sex; it is just a property of the noun.

Jante is a feminine noun, so words that go with it must match:

• a jante
• a jante limpa

You simply need to learn the noun together with its gender.

Because adjectives in Portuguese usually agree in gender and number with the noun they describe.

Since jante is feminine singular, the adjective must also be feminine singular:

• masculine singular: limpo
• feminine singular: limpa
• masculine plural: limpos
• feminine plural: limpas

So:

• O carro está limpo.
• A jante está limpa.
• As jantes estão limpas.

Portuguese often uses estar for a state or condition, especially one that can change, and ser for something more permanent or defining.

Here, clean is treated as a current condition, so estar is the natural choice:

• A jante está limpa. = The rim is clean.
  (It is clean right now.)

Using ser here would sound unusual in normal speech, because being clean is not seen as a permanent characteristic of the rim.

Here it is an adjective meaning clean.

It is true that limpa can also be a verb form of limpar:

• Ela limpa a jante. = She cleans the rim.

But in A jante está limpa, the structure is:

• noun + estar
  • adjective

So limpa is clearly an adjective in this sentence.

In European Portuguese, jante usually means the rim or wheel rim, especially of a car.

It is different from:

• roda = wheel
• pneu = tyre/tire

In everyday speech, people may sometimes use jante in contexts where English speakers might loosely think of the visible metal part of the wheel.

In normal Portuguese, you would usually keep the article: A jante está limpa.

Without the article, Jante está limpa sounds unnatural in ordinary speech. Portuguese generally uses articles more often than English does with common nouns.

So if you mean a specific rim, A jante is the normal form.

A careful European Portuguese pronunciation is approximately:

a ZHAN-tuh shtah LEEM-pah

A few useful points:

• j sounds like the s in measure
• está in European Portuguese often sounds closer to shtá
• the final -e in jante is very weak in Portugal
• limpa has clear stress on the first syllable: LIM-pa

A more phonetic version would be roughly [ɐ ˈʒɐ̃.tɨ ʃˈta ˈlĩ.pɐ] in European Portuguese.

The plural is:

As jantes estão limpas.

Each part changes to match the plural:

• a → as
• jante → jantes
• está → estão
• limpa → limpas

This shows how Portuguese makes articles, nouns, verbs, and adjectives work together.