Nemo fortem regit.

• nemo = the subject, in the nominative singular, meaning no one
• fortem = the direct object, in the accusative singular, from fortis, forte meaning brave
• regit = the verb, 3rd person singular present active indicative of regere

So the structure is basically subject + object + verb: No one [subject] rules the brave person [object].

Because fortem is in the accusative singular, which is the case used for a direct object after a verb like regit.

The adjective fortis, forte changes form depending on its job in the sentence:

• nominative singular: fortis = brave as a subject
• accusative singular: fortem = brave as a direct object

So fortem tells you that this is the person being ruled, not the one doing the ruling.

There are two clues:

1. nemo is nominative, the case normally used for the subject.
2. regit is singular, and nemo is also singular, so they match.

Meanwhile, fortem is accusative, so it is naturally read as the object.

Latin often tells you who is doing what by case endings, not just by word order.

By itself, fortem could be masculine or feminine accusative singular. The form is the same for both.

So grammatically it can mean:

• the brave man
• the brave woman
• more generally, the brave person

If your translation says the brave man, that is a reasonable choice, but the Latin form itself does not force that meaning unless context makes it clear.

Yes. Latin often uses an adjective by itself when the noun is understood. This is called a substantive adjective.

So fortem can mean something like:

• the brave man
• the brave one
• the brave person

An implied noun such as virum or hominem does not have to be stated.

regit comes from regere, meaning to rule, to guide, or to direct.

Its form is:

• present tense
• active voice
• indicative mood
• 3rd person singular

So regit means he/she/it rules or rules with a singular subject. Here the singular subject is nemo, so the whole sentence means no one rules ...

Because nemo already contains the negative idea. It already means no one.

So:

• nemo regit = no one rules

You do not need non as well. In fact, adding non would change the sense and would not be the normal way to say this simple idea.

Latin word order is much more flexible than English word order because the case endings show each word's role.

A verb at the end is very common in Latin, so Nemo fortem regit sounds natural.

You could rearrange the words, for example:

• Nemo regit fortem
• Fortem nemo regit

These have the same basic meaning, but the emphasis changes a little. The original sentence has a very standard Latin feel.

The dictionary form is fortis, forte.

That tells you it is a 3rd-declension adjective:

• fortis for masculine/feminine nominative singular
• forte for neuter nominative singular

The form fortem is one of its accusative singular forms.

Not always. The verb regere has a range of meanings, including:

• rule
• govern
• direct
• guide

Which English word is best depends on context. Even if your translation uses one specific meaning, it is helpful to know that the Latin verb itself is a little broader.