Iudex mendacium aperte improbat.

Latin usually has no articles. That means it normally does not have separate words for the or a/an.

So iudex can mean:

• judge
• a judge
• the judge

Which one is best in English depends on context. In this sentence, the judge is a natural translation.

We know from its case and from the verb.

Iudex is in the nominative singular, which is the case typically used for the subject of a sentence.

Also, the verb improbat is third person singular, so it matches a singular subject:

• iudex = the judge
• improbat = he/she/it disapproves

So iudex is the one doing the action.

Because mendacium is in the accusative singular, which is the case commonly used for the direct object.

That means it receives the action of the verb.

So in this sentence:

• iudex = subject
• mendacium = direct object

The judge is disapproving the lie.

Here is the breakdown:

• iudex = nominative singular
• mendacium = accusative singular

Why?

• iudex is the subject, so it is nominative.
• mendacium is the direct object, so it is accusative.

This is one of the most important patterns in Latin sentence reading.

Aperte is an adverb.

It modifies the verb improbat and tells us how the judge disapproves:

• openly
• plainly
• frankly

A quick clue: many Latin adverbs end in -e, especially ones formed from adjectives.

Latin word order is more flexible than English word order because Latin uses endings to show grammatical function.

In English, word order does much of the work:

• The judge disapproves the lie

In Latin, the endings already tell us who is doing what, so the words can move around more freely:

• Iudex mendacium aperte improbat
• Iudex aperte mendacium improbat
• Mendacium iudex aperte improbat

These can all mean roughly the same thing, though the emphasis may change.

Latin often puts the verb near the end, as here:

• improbat comes last

Improbat is a verb form from improbo, improbare, meaning:

• to disapprove
• to condemn
• to reject as bad

The form improbat is:

• present tense
• active voice
• indicative mood
• third person singular

So it means:

• he disapproves
• she disapproves
• it disapproves

In this sentence, with iudex as the subject, it means the judge disapproves.

In Latin, the verb ending often already tells you the subject.

The ending -t in improbat means third person singular:

• he
• she
• it

So Latin does not need to add a separate subject pronoun unless it wants special emphasis.

Because iudex is already present, the sentence does not need a word for he.

Iudex is grammatically a third-declension noun and is often masculine when referring to a male judge, but it can also refer to a female judge depending on context.

Latin grammatical gender and natural gender often overlap, but context matters. In many textbook sentences, iudex is treated as masculine by default, but the form itself does not force an English translation of male judge unless context does.

• iudex, iudicis is third declension
• mendacium, mendacii is second declension neuter

This helps explain their forms:

• third-declension nominative singular often has varied endings, so iudex does not end in -us
• second-declension neuter nouns often have -um in the nominative and accusative singular, so mendacium has that form here

Because mendacium is a second-declension neuter noun.

For neuter nouns in the second declension:

• nominative singular ends in -um
• accusative singular also ends in -um

So the form mendacium could be either nominative singular or accusative singular in isolation.

In this sentence, we know it is accusative singular because it is the direct object of improbat.

Yes. Latin adverbs are often fairly mobile.

For example, you could also have:

• Iudex aperte mendacium improbat
• Iudex mendacium improbat aperte
• Aperte iudex mendacium improbat

These all still mean roughly The judge openly disapproves the lie, though the emphasis can shift slightly depending on placement.

A common reconstructed Classical pronunciation would be roughly:

YOO-deks men-DAH-kee-um ah-PAIR-teh im-PROH-baht

A few helpful points:

• iudex begins with consonantal i, like y
• c is always hard, like k
• e is always pronounced clearly, never silent
• t is always pronounced

So mendacium has a hard k sound in the ci: men-DAH-kee-um, not like English sh or s.

Putting the verb at or near the end is very common in Latin, though it is not mandatory.

So Iudex mendacium aperte improbat feels quite natural:

• subject first
• object next
• adverb before the verb
• verb last

This is one reason Latin sentences can feel different from English even when the meaning is simple.

Not exactly as written.

This sentence most directly means that the judge disapproves a lie or the lie:

• mendacium = a specific lie, falsehood, or untruth as a noun

If you wanted the more general idea disapproves of lying, Latin might express that differently, often with another construction.

So the sentence points to a lie / the lie as an object, not the general activity lying.

That is because English and Latin use verbs differently.

In Latin, improbo can take a direct object:

• mendacium improbat = literally he disapproves the lie

But idiomatic English usually says:

• he disapproves of the lie

So the of appears in English because that is the natural English pattern, not because there is a separate Latin word corresponding to it.