זה עסק קטן.

Because in present-tense Hebrew, the verb to be is usually left out.

So Hebrew often says the equivalent of:

• זה עסק קטן
• literally: this / business / small

but it means:

• This is a small business

If you want was or will be, then Hebrew usually does use a verb:

• זה היה עסק קטן = This was a small business
• זה יהיה עסק קטן = This will be a small business

Here זה means something like this or this is.

In this kind of sentence, זה + noun phrase is a very common way to identify something:

• זה בית = This is a house
• זה רעיון טוב = This is a good idea

So in זה עסק קטן, the זה helps make it a full sentence. Without it, עסק קטן would usually just mean a small business as a phrase, not a complete sentence.

In Hebrew, adjectives usually come after the noun they describe.

So:

• עסק קטן = business small = small business
• בית גדול = house big = big house

This is the normal Hebrew pattern:

• noun + adjective

Because Hebrew adjectives must agree with the noun in gender and number.

עסק is masculine singular, so the adjective must also be masculine singular:

• עסק קטן = masculine singular

Compare:

• חנות קטנה = small store
  because חנות is feminine singular, the adjective becomes קטנה

So קטן matches עסק correctly.

Hebrew has no indefinite article. There is no separate word for a or an.

So:

• עסק קטן can mean a small business

If you want the, Hebrew does mark that:

• העסק הקטן = the small business

Notice that with adjectives, both the noun and the adjective usually get ה־ when the phrase is definite:

• העסק הקטן
• not just העסק קטן if you mean the small business as a noun phrase

A common pronunciation is:

• ze é-sek ka-TAN

More roughly:

• זה = ze
• עסק = EH-sek
• קטן = ka-TAN

A couple of helpful notes:

• The stress in עסק is usually on the first syllable: É-sek
• The stress in קטן is on the last syllable: ka-TAN
• The letter ע in עסק is often very weak or effectively silent in modern Israeli Hebrew

Usually, זה עסק קטן is understood as:

• This is a small business

If you want to say:

• This business is small

Hebrew would more naturally say:

• העסק הזה קטן

That sentence literally means:

• the business this small

So the word order changes the meaning:

• זה עסק קטן = This is a small business
• העסק הזה קטן = This business is small

In standard Hebrew, זה is the masculine singular demonstrative pronoun.

The feminine counterpart is:

• זאת or זו

So in very careful standard Hebrew, you may see:

• זאת חנות קטנה = This is a small store

However, in everyday spoken Hebrew, זה is often used very broadly, even in places where a learner might expect זאת. So learners will hear זה a lot.

You would say:

• העסק הקטן

This is a useful pattern to remember:

• עסק קטן = a small business
• העסק הקטן = the small business

In Hebrew, when a noun is definite and has an adjective, the adjective usually becomes definite too:

• ה + noun
• ה + adjective

So both words take ה־.