Puer non dormit; immo per fenestram lunam spectat.

Latin does not have articles like English the and a/an. So puer can mean the boy or a boy, depending on context.

In this sentence, puer is also in the nominative singular, which tells you it is the subject of the verb.

You can tell from its form and from the verb.

• puer is nominative singular, the case normally used for the subject.
• dormit and spectat are both third person singular, so they go naturally with a singular subject like puer.

So puer is the one doing the actions: not sleeping and looking.

In Latin, non normally comes right before the word it negates, especially before a verb.

So:

• non dormit = he is not sleeping

That is the most ordinary and expected placement.

Immo is a correcting or strengthening word. Here it means something like:

• no, rather
• indeed instead
• on the contrary

So the sentence first says that the boy is not sleeping, and then immo replaces that idea with the real one: he is actually doing something else.

The semicolon helps show a strong pause and a contrast between the two parts:

• Puer non dormit
• immo per fenestram lunam spectat

It works a bit like English punctuation in a sentence such as:

• The boy is not sleeping; rather, he is looking at the moon through the window.

It is not a special Latin grammar rule, just a helpful way to punctuate the contrast.

Because per means through, and it takes the accusative case.

So:

• fenestra = window as a dictionary form / nominative
• fenestram = accusative singular, required after per

That is why the phrase is per fenestram = through the window.

Because lunam is the direct object of spectat.

The verb spectare means to look at, watch, or observe, and the thing being looked at is put in the accusative.

So:

• luna = nominative, the moon as subject
• lunam = accusative, the moon as object

Here the boy is looking at the moon, so Latin uses lunam.

Latin often expresses an object directly with the accusative, where English needs a preposition.

English says:

• look at the moon

But Latin can simply say:

• lunam spectat

That is normal with spectare. You do not need a separate word for at here.

Yes, Latin word order is much freer than English word order because the endings show the grammatical roles.

This sentence could also be written in other ways, such as:

• Puer non dormit; immo lunam per fenestram spectat.
• Puer non dormit; immo spectat lunam per fenestram.

The given order is perfectly natural. It places the prepositional phrase per fenestram before lunam spectat, which can help set the scene first: through the window, he looks at the moon.

Both are:

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

So they mean:

• dormit = he/she sleeps or is sleeping
• spectat = he/she looks at, is looking at

Because the subject is puer, in context both mean he.

Latin usually does not need an expressed subject pronoun, because the verb ending already tells you the person and number.

For example:

• dormit already means he/she/it sleeps
• spectat already means he/she/it looks

Since puer is already stated, adding he would be unnecessary.

It can cover several related ideas, depending on context:

• looks at
• watches
• observes

In this sentence, looks at is probably the most straightforward choice, but watches the moon through the window could also fit the Latin well. The exact English wording depends on the translation style, not on a grammatical difference.

Not literally. Per means through, so the basic image is that the boy’s gaze passes through the window.

In natural English, people might translate more freely as:

• through the window
• out the window
• out of the window

But grammatically, the Latin phrase itself is through the window.