Parma hoplomacho utilis est.

It is:

• parma = the subject
• hoplomacho = a dative word, meaning to/for the hoplomachus
• utilis = a predicate adjective, useful
• est = is

So the structure is basically:

subject + dative complement + predicate adjective + linking verb

In very literal English: A shield is useful to/for a hoplomachus.

Because it is the word that utilis est is describing.

A predicate adjective like utilis agrees with the subject, and here parma is the noun that fits that role: the shield is useful.

If you are reading without macrons, parma could look ambiguous by form alone, but the sentence structure makes it clear that it is functioning as the nominative subject here.

Because utilis commonly takes the dative for the person or thing that something is useful to or for.

So:

• utilis alicui = useful to someone
• hoplomacho = to/for the hoplomachus

This is very common in Latin. English often uses to or for, but Latin often uses the dative ending instead.

You can think of it that way if that helps, but more precisely it is a dative with an adjective.

In other words, it is not the indirect object of a verb like give or show. Instead, it depends on the adjective utilis.

So the most exact explanation is:

• hoplomacho = dative complement with utilis

Because utilis is a third-declension adjective, not a first/second-declension one.

Its nominative singular forms are:

• masculine: utilis
• feminine: utilis
• neuter: utile

So even though parma is feminine, the correct nominative singular feminine form is still utilis, not utila.

It agrees with parma.

A predicate adjective in Latin agrees with the noun it describes in:

• gender
• number
• case

So here utilis is feminine, singular, and nominative to match parma.

Because Latin often expresses that idea just by using the dative ending.

So instead of saying:

• to the hoplomachus
• for the hoplomachus

Latin can simply say:

• hoplomacho

The ending -o is doing the work that English usually does with a preposition.

Either is possible.

Latin has no articles like a, an, or the. So parma can mean:

• a shield
• the shield
• sometimes just shield, depending on context

You decide from the situation, not from the word itself.

Yes. Latin word order is much more flexible than English word order.

This sentence could be rearranged in several ways without changing the basic meaning, for example:

• Parma hoplomacho utilis est
• Parma utilis hoplomacho est
• Hoplomacho parma utilis est

The endings show the grammar, so the order is often used for emphasis or style, not to mark the basic roles.

Because Latin often puts the verb near or at the end of the sentence.

That is a very common Latin pattern, especially in simple textbook sentences:

• subject first
• other information in the middle
• verb last

So est at the end is completely normal Latin word order.

It is a Greek-derived word that has been adapted into Latin.

In Latin it is treated like a second-declension masculine noun, so its dative singular is hoplomacho.

That is why the ending is -o here.

Sometimes yes. Latin can omit forms of esse (to be) when the meaning is obvious.

So in some contexts you might find something like:

• Parma hoplomacho utilis

with est understood.

But in a clear teaching sentence, keeping est is perfectly normal and helpful.