Krađa je zlo.

A natural pronunciation is approximately:

KRAH-jah yeh ZLOH

A bit more precisely:

• krađa ≈ KRAH-djah
  
  • đ is a soft sound, similar to the j in judge, but lighter.
• je = yeh
• zlo = zloh

Stress is usually on the first syllable of krađa: KRÂ-đa.

Je is the 3rd person singular present form of the verb biti (to be).

So:

• ja sam = I am
• ti si = you are
• on/ona/ono je = he/she/it is

In Krađa je zlo, je simply means is.

Croatian does not use articles like English the and a/an.

So Krađa je zlo can mean:

• Theft is evil
• Theft is a bad thing
• Theft is evilness / an evil

The exact English wording depends on context, but Croatian does not need an article here.

Krađa is in the nominative singular.

It is the subject of the sentence:

• krađa = theft

This is also the dictionary form of the noun.

Here zlo is also in the nominative singular.

With the verb biti (to be), Croatian often uses the nominative for both:

• the subject
• the predicate noun / predicate complement

So:

• Krađa = subject
• zlo = what theft is

That is why you get Krađa je zlo, not a different case.

Here it is best understood as a noun.

• zlo = evil, wrong, something bad

So the structure is basically:

• Theft is evil / a wrong / an evil thing

Croatian also has adjective forms related to this idea, but in this sentence zlo functions as a noun.

Yes, but it means something slightly different in tone.

• Krađa je zlo. = Theft is evil.
• Krađa je loša. = Theft is bad.

Zlo sounds stronger and more moral/philosophical.
Loša is more like bad.

Also note:

• loša is an adjective
• it agrees with krađa, which is a feminine singular noun

That is why it is loša, not loš or loše.

In Croatian, nouns have grammatical gender: masculine, feminine, neuter.

Krađa is a feminine noun. One clue is that it ends in -a, which is very common for feminine nouns.

This does not mean theft is female in any real-world sense. It is just grammatical gender.

Gender matters because adjectives and some other words must match it:

• Krađa je loša.
• not Krađa je loš.

Yes, Croatian word order is more flexible than English, but not every version sounds equally natural.

The normal neutral order is:

• Krađa je zlo.

You may also see other orders in special contexts for emphasis, but for a learner, Krađa je zlo is the best standard form to use.

Yes. It is a fully complete and natural sentence.

It contains:

• a subject: krađa
• a verb: je
• a predicate complement: zlo

Croatian does allow some short sentences without an expressed subject in many cases, but here the subject is explicitly present.

In the present tense, Croatian usually does include the verb biti in normal statements like this.

So:

• Krađa je zlo. = correct

Leaving out je here would sound wrong.

You may notice omission of to be in some special styles, headlines, poetry, or other structures, but not in an ordinary sentence like this one.

Krađa is a noun meaning theft or stealing.

It comes from the verb krasti (to steal).

So there is a useful connection:

• krasti = to steal
• krađa = theft

This is similar to English:

• to steal
• theft

Yes. Zlo is a neuter singular noun.

A very common pattern in Croatian is:

• many neuter nouns end in -o or -e

So in this sentence:

• krađa = feminine noun
• zlo = neuter noun

That is perfectly normal, because they do not have to match in gender when both are nouns.
Gender agreement matters with adjectives, not in the same way with predicate nouns.

Not exactly.

• Krađa je zlo. = Theft is evil / theft is a bad thing.
• To je zlo. = That is evil / that is a bad thing.

To means that or it, so it refers to something already understood from context.
Krađa specifically names the subject.

It sounds neutral and standard, though the word zlo gives it a somewhat moral or weighty tone.

So it is perfectly grammatical and normal, but it sounds a bit stronger than a casual everyday comment like:

• Krađa je loša.
• Nije u redu krasti. = It’s not okay to steal.

So Krađa je zlo is simple, correct, and slightly emphatic in meaning.