Policista napsal moje příjmení.

Policista is the nominative singular form, which is the form used for the subject of the sentence.

Here, policista is the person doing the action, so nominative is required:

• Policista napsal moje příjmení.
• The police officer wrote my surname.

It is a masculine animate noun.

Napsal is the past tense, masculine singular form of napsat.

In Czech past tense, the verb agrees with the subject in gender and number:

• policista napsal = a male police officer wrote
• policistka napsala = a female police officer wrote
• policisté napsali = police officers wrote

So the -l tells you the subject is masculine singular.

This is a question of aspect, which is very important in Czech.

• napsal comes from napsat = perfective
• psal comes from psát = imperfective

In this sentence, napsal suggests a completed action: he wrote it down, finished writing it.

So:

• napsal moje příjmení = he wrote down my surname / he completed writing it
• psal moje příjmení could mean he was writing my surname, or simply focuses on the process rather than completion

In many real-life contexts like forms, reports, or documents, napsal is very natural.

Moje is agreeing with příjmení, and the whole phrase is the direct object of the verb, so it is in the accusative.

However, for many neuter singular nouns, the nominative and accusative forms are the same. That is why you see:

• moje příjmení in nominative
• moje příjmení in accusative

So although it is the object, the form does not visibly change here.

Both are possible.

• moje příjmení
• mé příjmení

Both mean my surname.

In everyday Czech, moje is often more common and natural in speech.
Mé can sound a bit more formal, literary, or stylistically marked in some contexts.

So this sentence is completely normal with moje.

It is in the accusative singular, because it is the thing affected by the action of the verb napsal.

The police officer wrote what?
→ moje příjmení

That makes it the direct object.

A useful thing to know is that příjmení is a neuter noun, and in the singular its nominative and accusative look the same.

Here it is singular and means surname or last name.

The ending -í does not mean plural here. Czech has a number of neuter nouns ending in -í, for example:

• jméno = name
• příjmení = surname
• náměstí = square

So příjmení is just a singular noun with that noun pattern.

Czech has no articles, so there is no direct equivalent of a or the.

That means Policista can mean:

• a police officer
• the police officer

Which meaning is intended depends on the context.

So the sentence could be understood as either:

• The police officer wrote my surname
• A police officer wrote my surname

depending on the situation.

Yes. Czech word order is more flexible than English because cases help show grammatical roles.

The basic neutral order here is:

• Policista napsal moje příjmení.

But other orders are possible, for example:

• Moje příjmení napsal policista.
• Policista moje příjmení napsal.

These may sound more emphatic or may highlight a different part of the sentence.

In neutral everyday use, the original order is very natural.

Grammatically, yes: policista is a masculine noun, and the verb napsal also shows masculine agreement.

If the police officer were female, you would normally say:

• Policistka napsala moje příjmení.

So this sentence specifically refers to a male police officer.

The sentence Policista napsal moje příjmení already strongly suggests wrote down because napsat often implies successfully writing something.

But if you want a more explicit idea of entering or recording information, Czech might also use verbs such as:

• zapsal moje příjmení = wrote down / recorded my surname
• zaznamenal moje příjmení = recorded my surname

So napsal is correct and natural, but depending on context, another verb might be even more precise.