Lokata terminowa ma wysokie oprocentowanie.

Because lokata is a feminine singular noun, and terminowa is an adjective describing it, so the adjective must agree with the noun in gender, number, and case.

• lokata = a deposit / bank deposit
• terminowa = term / fixed-term

Since lokata is feminine singular, the adjective also takes the feminine singular form:

• terminowy → masculine
• terminowa → feminine
• terminowe → neuter

So lokata terminowa is a normal adjective + noun combination with agreement.

Ma means has, from the verb mieć (to have).

So the structure is literally:

• Lokata terminowa ma wysokie oprocentowanie
  = A fixed-term deposit has high interest / a high interest rate

In Polish, this is a very natural way to express this idea. English might also say:

• The deposit has a high interest rate
• The deposit offers high interest
• The deposit is highly interest-bearing (less common in everyday English)

If you used jest, you would need a different structure, for example:

• Lokata terminowa jest wysoko oprocentowana
  = The fixed-term deposit is highly interest-bearing / has a high rate of interest

So ma is not the only possibility, but it is completely natural here.

It is in the accusative case, because it is the direct object of ma (has).

The sentence structure is:

• Lokata terminowa = subject
• ma = verb
• wysokie oprocentowanie = direct object

However, for many neuter singular nouns, the accusative looks exactly the same as the nominative. That is what happens here:

• nominative: oprocentowanie
• accusative: oprocentowanie

So even though the form does not change, the function is accusative.

Because wysokie must agree with oprocentowanie, and oprocentowanie is a neuter singular noun.

Adjective agreement here is:

• wysoki = masculine singular
• wysoka = feminine singular
• wysokie = neuter singular

So:

• wysokie oprocentowanie = correct
• wysoki oprocentowanie = wrong
• wysoką oprocentowanie = wrong

Also, because the noun is neuter singular and serves as a direct object, the accusative form of the adjective is also wysokie.

A very common clue is the ending -e or -o in dictionary/basic form, but in this case the noun ends in -anie / -enie / -cie, which are very often neuter verbal nouns in Polish.

Examples:

• oprocentowanie = interest rate / interest-bearing level
• mieszkanie = apartment / living
• pytanie = question
• czytanie = reading

These are usually neuter, which is why the adjective is wysokie.

No. Polish has no articles like English a/an/the.

So Lokata terminowa ma wysokie oprocentowanie can mean, depending on context:

• A fixed-term deposit has high interest
• The fixed-term deposit has high interest
• A fixed-term deposit has a high interest rate
• The fixed-term deposit has a high interest rate

Context tells you which one is meant.

Not completely. Polish word order is more flexible than English, because case endings help show grammatical roles.

The neutral, standard order here is:

• Lokata terminowa ma wysokie oprocentowanie.

You could also rearrange it for emphasis, for example:

• Wysokie oprocentowanie ma lokata terminowa.

But that sounds marked or contrastive, not neutral. A learner should generally stick with:

• subject + verb + object

So this sentence is a good standard model.

Yes. That is also correct, but it is a different structure.

Compare:

• Lokata terminowa ma wysokie oprocentowanie.
  Literally: The fixed-term deposit has high interest / a high interest rate.

• Lokata terminowa jest wysoko oprocentowana.
  Literally: The fixed-term deposit is highly interest-bearing / is highly financed with interest.

The second version uses:

• jest = is
• wysoko oprocentowana = highly interest-bearing / carrying high interest

Both are natural, though the first one is often easier for learners because the grammar is more straightforward.

This is a very useful vocabulary distinction.

• oprocentowanie usually refers to the interest rate or the level/rate of interest
• odsetki usually refers to the interest money itself, the amount paid/earned

So:

• wysokie oprocentowanie = a high interest rate
• wysokie odsetki = high interest payments / a high amount of interest

In banking language, oprocentowanie is the better fit in this sentence.

A rough English-friendly pronunciation is:

• loh-KAH-tah ter-mee-NOH-vah mah vee-soh-KYEH oh-proh-tsen-toh-VAH-nyeh

A few useful sound notes:

• ł sounds like English w
• w sounds like English v
• c sounds like ts
• ie in wysokie sounds like ye
• nie at the end of oprocentowanie sounds roughly like nye

If you want a slower chunking:

• Lokata terminowa
• ma
• wysokie oprocentowanie

Yes. It is a standard and natural banking expression for a fixed-term deposit or term deposit.

You may also see related words such as:

• lokata = deposit account / deposit
• depozyt = deposit
• konto oszczędnościowe = savings account

But lokata terminowa is the normal phrase for this specific product.

Yes. In practice, English may translate it in more than one way depending on context.

Most precisely in banking, it often means:

• a high interest rate

But in more general English, people may simply say:

• high interest

So if you are learning Polish, it is best to understand oprocentowanie here as the rate/level of interest, not just the money earned.