Ta decyzja ma dobrą podstawę.

Here is the breakdown:

• ta — this, feminine singular, nominative
• decyzja — decision, feminine singular, nominative
• ma — has, 3rd person singular of mieć
• dobrą — good, feminine singular, accusative
• podstawę — basis / foundation / grounds, feminine singular, accusative

So the structure is basically:

This decision + has + a good basis

The subject is ta decyzja, and the direct object is dobrą podstawę.

Because decyzja is a feminine noun.

In Polish, this changes depending on gender:

• ten for masculine nouns
• ta for feminine nouns
• to for neuter nouns

Since decyzja is feminine, you say:

• ta decyzja = this decision

Not ten decyzja.

Because dobrą podstawę is the direct object of the verb ma.

The verb mieć usually takes the accusative case, so both the adjective and the noun must change form.

Dictionary forms:

• dobra podstawa = good basis
  
  • nominative
• dobrą podstawę = good basis
  
  • accusative

This is a very common pattern with feminine singular nouns ending in -a:

• noun: -a → -ę
• adjective: -a → -ą

So:

• podstawa → podstawę
• dobra → dobrą

Ma is the 3rd person singular form of mieć, meaning to have.

Literally, the sentence means:

• This decision has a good basis

In English, you might also translate it more naturally depending on context as:

• This decision is well-founded
• This decision has good grounds
• This decision is based on solid grounds

But in Polish, using ma here is completely normal.

In this context, podstawa means something like:

• basis
• foundation
• grounds
• justification

It does not necessarily mean a physical foundation here. It is more abstract.

So dobrą podstawę suggests that the decision is supported by good reasons, evidence, or logic.

Yes, it is natural, especially in formal, analytical, legal, or administrative contexts.

It sounds like something you might read or hear when discussing whether a decision is justified.

In more everyday speech, people might also say things like:

• Ta decyzja jest uzasadniona. = This decision is justified.
• Ta decyzja ma sens. = This decision makes sense.

But Ta decyzja ma dobrą podstawę is perfectly correct and natural.

Yes. Polish word order is more flexible than English word order.

The neutral, standard order is:

• Ta decyzja ma dobrą podstawę.

But you could also change the order for emphasis, for example:

• Dobrą podstawę ma ta decyzja.
  This emphasizes good basis.

Even though the order can change, the case endings still show what each word is doing.

So learners should usually start with the neutral order and only later explore emphasis-based variations.

You know from the case endings.

• decyzja is in the nominative, which is the usual case for the subject
• podstawę is in the accusative, which is the usual case for the direct object after mieć

So even if word order changed, the endings would still help you identify the roles.

That is one of the big differences between Polish and English:
Polish often shows grammatical function through endings, not only through position in the sentence.

Because adjectives in Polish must agree with the noun they describe in:

• gender
• number
• case

The noun here is podstawę, which is:

• feminine
• singular
• accusative

So the adjective must match it:

• dobra podstawa — nominative
• dobrą podstawę — accusative

This agreement is a core feature of Polish grammar.

A simple English-friendly approximation is:

• deh-CYZ-ya

A few helpful points:

• cz / sz are not in this word
• zj in decyzja sounds like a soft zh/y combination
• the stress is on the second-to-last syllable: CYZ

So:

• de-CYZ-ja

Also:

• dobrą ends with ą, which is a nasal vowel
• podstawę ends with ę, another nasal vowel

Learners often pronounce these as a plain o or e at first, which is common, but it is good to notice that they are special Polish vowels.