Noli foras currere; Marcus enim prorsus oblitus est se caligas nondum induisse.

Noli currere is the normal Latin way to give a negative command to one person: do not run.

• noli = singular imperative of nolo (to be unwilling)
• currere = to run

So literally it is something like be unwilling to run, but idiomatically it simply means don’t run.

If you were speaking to more than one person, Latin would use nolite + infinitive.

Foras means outside or out of doors. It often expresses motion toward the outside, not just location.

So:

• foris = outside, outdoors
• foras = to the outside, outside

That fits well with currere, since running suggests movement: Don’t run outside.

Latin very often places enim after the first word or phrase of its clause. This is a normal habit of the language.

So in:

Marcus enim prorsus oblitus est...

enim means for, you see, or after all, and it appears after Marcus because that is where Latin commonly puts it.

You should not expect it to stand at the very beginning the way English for sometimes does.

Prorsus means completely, entirely, or absolutely.

So:

• oblitus est = he forgot / has forgotten
• prorsus oblitus est = he completely forgot

It strengthens the idea. The speaker is not saying Marcus merely overlooked something a little; he completely forgot it.

Oblitus est is the perfect tense of the deponent verb obliviscor (to forget).

Deponent verbs are passive in form but active in meaning. So although oblitus est looks like a passive perfect, it actually means he forgot or he has forgotten.

Breakdown:

• oblitus = perfect participle form
• est = is/has

Together in a deponent verb, they give an active meaning: he forgot.

Depending on context, English may translate it as either:

• forgot
• has forgotten

Se is a reflexive pronoun meaning himself, herself, itself, or themselves, depending on context.

Here it refers back to Marcus:

• Marcus ... oblitus est se caligas nondum induisse
• Marcus forgot that he had not yet put on his boots

Latin uses se because in indirect statement the subject of the subordinate idea is often put in the accusative, and if that subject is the same as the main subject, Latin uses the reflexive pronoun.

So se = himself, meaning Marcus himself.

This is a standard Latin construction called indirect statement (often abbreviated ACI, for accusative + infinitive).

After verbs of saying, thinking, knowing, perceiving, remembering, forgetting, and similar ideas, Latin often expresses that... clauses with:

• an accusative subject
• an infinitive verb

So instead of saying:

• Marcus forgot that he had not yet put on his boots

Latin says, more literally:

• Marcus forgot himself not yet to have put on his boots

Here:

• se = accusative subject of the indirect statement
• induisse = infinitive verb of the indirect statement

This is one of the most important Latin constructions to learn.

Induisse is the perfect active infinitive of induere (to put on).

It is perfect because the putting-on would have happened before the forgetting. Marcus forgot the fact that he had not yet put on his boots.

So the sequence is:

1. he had not put on the boots yet
2. he forgot that fact

That is why Latin uses the perfect infinitive in the indirect statement.

Caligas is the direct object of induisse.

• caliga, caligae = a boot, especially a heavy military-style boot
• caligas = boots in the accusative plural

Since induere means to put on, it takes the thing put on as its direct object:

• caligas induere = to put on boots

So caligas is accusative because it is what Marcus had not yet put on.

Nondum means not yet.

That is stronger and more specific than plain non, which would only mean not.

Compare:

• non induisse = not to have put on
• nondum induisse = not yet to have put on

Here the idea is that Marcus had still not done it at that point. The yet is important: he was supposed to have put on the boots already, but had not done so.

Yes. Latin word order is flexible, and this sentence uses that flexibility naturally.

Noli foras currere; Marcus enim prorsus oblitus est se caligas nondum induisse.

A few points:

• noli comes first because the command is urgent.
• foras is placed before currere, which keeps run outside closely connected.
• Marcus enim follows the common pattern of placing enim second.
• prorsus stands near oblitus est to intensify the forgetting.
• nondum comes right before induisse, emphasizing had not yet put on.

Latin word order often highlights emphasis and rhythm more than strict grammatical relations, because the endings already show the grammar.

Yes. The verb obliviscor can be used in more than one way in Latin.

A learner may also meet it with:

• a genitive: rei oblitus est = he forgot the thing
• sometimes other constructions depending on author and period

But in this sentence, the speaker is not merely naming a thing forgotten. Instead, the sentence expresses a full idea: that he had not yet put on his boots. For that, the indirect statement with se ... induisse is very natural.