Mater dicit pretium mercatoris iniustum esse.

The main clause is:

• Mater = mother; nominative singular, the subject
• dicit = says

Then Latin uses an indirect statement after dicit:

• pretium mercatoris iniustum esse

Literally, that part is something like:

• the merchant's price to be unjust

So the whole sentence means:

• Mother says that the merchant's price is unjust.

Esse is the present infinitive of sum, meaning to be.

After verbs like dicit (says), Latin very often uses an accusative + infinitive construction instead of a clause with that. So where English says:

• Mother says that the price is unjust

Latin says more literally:

• Mother says the price to be unjust

That is why esse appears.

Because classical Latin usually expresses indirect statements with the accusative and infinitive construction, not with a separate word like English that.

So:

• English: Mother says that the merchant's price is unjust
• Latin: Mater dicit pretium mercatoris iniustum esse

Latin can use other constructions in some contexts, but after verbs of saying, thinking, knowing, hearing, and so on, the accusative + infinitive is extremely common.

In an indirect statement, the subject of the infinitive goes into the accusative.

Here, the thing that is unjust is pretium. In English that would be the subject of is:

• the price is unjust

But in Latin indirect statement, that subject becomes accusative:

• pretium ... esse

One important detail: pretium is a neuter second-declension noun, so its nominative singular and accusative singular look the same. The form pretium could be either nominative or accusative by shape alone, but here its job in the sentence shows that it is accusative.

Mercatoris is genitive singular of mercator, meaning merchant.

The genitive often shows possession or close relationship, so:

• pretium mercatoris = the merchant's price or the price of the merchant

So mercatoris depends on pretium.

Because it agrees with pretium.

Iniustus, iniusta, iniustum means unjust / unfair. Since pretium is:

• neuter
• singular

the adjective must also be:

• neuter
• singular

So we get:

• pretium ... iniustum esse

In the indirect statement, you can think of iniustum as matching the accusative subject pretium, though for neuter singular the nominative and accusative forms are identical anyway.

It can mean either, depending on context.

With pretium (price), English often naturally says:

• unfair
• unjust
• sometimes even too high is implied by context, though that is not built into the word itself

So pretium mercatoris iniustum esse is most directly that the merchant's price is unfair/unjust.

Latin word order is more flexible because the endings show each word's role.

Here:

• Mater is nominative, so it is the subject.
• dicit is the main verb.
• mercatoris is genitive, so it means of the merchant.
• esse marks the infinitive of the indirect statement.

Because of those endings, Latin does not need to rely on word order as heavily as English does.

This sentence is quite natural as written, but other orders are possible, such as:

• Mater pretium mercatoris iniustum esse dicit.

That means the same thing.

Dicit is:

• present tense
• third person singular
• active voice

from the verb dico, dicere, meaning to say.

So it means:

• he says
• she says
• it says

Here, because the subject is mater, it means mother says.

Latin has no articles like English the or a/an.

So:

• mater can mean mother, a mother, or the mother
• pretium can mean price, a price, or the price

The context tells you which English article makes most sense. In this sentence, English naturally uses:

• Mother says that the merchant's price is unjust.

Grammatically, the genitive has several uses, but here the most natural one is possessive or descriptive:

• pretium mercatoris = the merchant's price

That usually means the price set by the merchant, the price belonging to the merchant's goods, or the merchant's asking price.

So in this sentence, learners should understand it simply as the merchant's price.

Yes. Mater is the nominative singular of mater, matris, meaning mother.

It is the subject of dicit, so nominative is exactly what we expect.

A learner may notice that mater does not end in -a, unlike many feminine nouns. That is because it belongs to the third declension, not the first.

Yes, and that is often useful.

A very literal breakdown is:

• Mater = mother
• dicit = says
• pretium mercatoris = the merchant's price
• iniustum esse = to be unjust

So the whole thing is:

• Mother says the merchant's price to be unjust

That sounds unnatural in normal English, but it helps you see how the Latin construction works. Then you can turn it into good English:

• Mother says that the merchant's price is unjust.