Lusor de iactu gloriatur.

Because glorior is a deponent verb. Deponent verbs use passive-looking forms but have an active meaning.

So gloriatur looks like a passive form, but it means he/she boasts, not he/she is boasted.

This is something English speakers often have to get used to in Latin:

• sequitur = he/she follows
• loquitur = he/she speaks
• gloriatur = he/she boasts

Gloriatur is:

• 3rd person singular
• present tense
• indicative mood
• from the deponent verb glorior, gloriari

So it means he boasts, she boasts, or boasts, depending on context.

Because it is present tense, it can also sometimes be understood as is boasting in English.

The subject is lusor.

You can tell because lusor is in the nominative singular, which is the case normally used for the subject of a finite verb.

Latin does not rely on word order as heavily as English does. Instead, it uses case endings to show what each word is doing in the sentence.

So even if the order changed, lusor would still be the subject as long as it stayed nominative.

Lusor is a third-declension noun.

Its dictionary form would be something like:

• lusor, lusoris = player, gamer, sportsman, sometimes gambler, depending on context

In this sentence, it is nominative singular.

It is also an agent noun: a noun meaning a person who does something. Latin often makes such nouns with -or.

Because glorior often takes de + ablative to mean boast about or boast of something.

So:

• de iactu = about the throw / of the throw

A learner should not try to translate de the same way every time. Its basic sense is often something like about, concerning, from, or down from, depending on context. Here, with gloriatur, it means about or of.

Iactu is ablative singular.

You know this for two reasons:

1. de takes the ablative
2. iactus is a fourth-declension noun, and its ablative singular ends in -u

So the form is:

• nominative: iactus
• genitive: iactus
• dative: iactui
• accusative: iactum
• ablative: iactu

Because it comes after de, it must be ablative here.

Because Latin has no articles.

So lusor can mean:

• the player
• a player

and iactu can mean:

• about the throw
• about a throw

The context, or the translation provided in your textbook, tells you which is most natural in English.

This is very normal in Latin: you often have to supply the or a/an when translating.

Yes, it could be different.

Latin word order is much more flexible than English word order because the endings show grammatical relationships. The sentence could be rearranged without changing the basic meaning, for example:

• De iactu lusor gloriatur
• Gloriatur lusor de iactu

That said, the given order is very natural:

• lusor first introduces the topic
• de iactu adds what he is boasting about
• gloriatur comes at the end, which is very common in Latin prose

So this order sounds normal and clear.

It can mean either, depending on context.

Latin present tense often covers both:

• simple present: boasts
• progressive present: is boasting

So gloriatur could be translated either way in principle. English usually chooses whichever sounds better in the situation.

Yes. Lusor is related to ludo, which means I play.

Latin often forms nouns meaning a person who does X from verbs. So:

• ludo = I play
• lusor = player

This can help with vocabulary building: once you recognize endings like -or, you can often guess that the word refers to a person performing an action.