La kuriero foriris sen ke mi subskribis ion.

Foriris is for- + iris.

• iri = to go
• iris = went
• for- adds the idea of away, off, or leaving from a place

So foriris means went away, left, or departed.

That prefix is very common in Esperanto:

• foriri = go away, leave
• fordoni = give away
• forpreni = take away

Because sen ke is the normal way to say without when what follows is a full clause with its own subject and verb.

Here the part after it is a full clause:

• mi = subject
• subskribis = verb
• ion = object

So:

• sen ke mi subskribis ion = without me signing anything

Compare:

• sen akvo = without water
• sen subskribo = without a signature
• sen ke mi subskribis ion = without my signing anything

If you need a whole mini-sentence after without, Esperanto often uses sen ke.

Because ke introduces the subordinate clause.

In English, we often do not need an extra word in without signing anything, but Esperanto commonly uses ke in sen ke when a finite verb follows.

So sen ke works together as a set expression meaning something like:

• without it being the case that...
• more naturally, just without...

You should think of sen ke as a chunk, not as two completely separate choices.

Because this clause has its own subject: mi.

• subskribi is an infinitive: to sign
• subskribis is a finite verb: signed

In Esperanto, when you say who is doing the action inside that subordinate idea, a finite clause is very natural:

• sen ke mi subskribis ion

Using just an infinitive would not work the same way here, because the sentence needs to show that I was the one who would have signed.

A rough contrast:

• Li foriris sen adiaŭi. = He left without saying goodbye.
  Same subject, so the infinitive works well.

• La kuriero foriris sen ke mi subskribis ion. = The courier left without me signing anything.
  Different subject, so sen ke

  • finite verb is clearer.

Because the whole situation is in the past.

• foriris = left
• subskribis = signed

Both are viewed from a past-time perspective.

Very importantly, subskribis here does not mean that the signing actually happened. The non-happening comes from sen ke.

So the idea is:

• the courier left
• and the signing did not happen before that

The past tense simply places that non-event in the same past timeframe.

On its own, yes, subskribis means signed. But inside sen ke..., the whole clause is under the idea of without.

So:

• mi subskribis ion alone = I signed something
• sen ke mi subskribis ion = without my signing anything

In other words, the verb form shows time, while sen ke shows that the event did not take place as part of the actual outcome.

This is similar to English:

• He left without my signing anything

The verb idea is still sign, but the whole construction says it never happened.

Because ion is the direct object of subskribis.

• io = something
• ion = something / anything as an object

Since subskribi is something you do to a thing, the object takes -n:

• subskribi dokumenton = to sign a document
• subskribi ion = to sign something / anything

So the -n here is just the normal accusative ending for a direct object.

Because sen already gives the sentence its negative-like meaning of without.

So ion here is naturally understood like English anything:

• sen ke mi subskribis ion = without me signing anything

Using nenion would usually be unnecessary and could make the logic awkward. Esperanto often avoids piling on extra negative words when the lack is already clear from another word like sen.

So in this sentence, ion is the normal choice.

Because sen ke already expresses the idea of without.

If you added ne, you would be changing the logic and making the clause harder to interpret. The sentence does not need a second negative marker.

So:

• sen ke mi subskribis ion = without my signing anything

That already says the signing did not happen.

Here subskribi means to sign.

It is built from:

• sub = under
• skribi = write

So literally it is something like write underneath, which matches the idea of signing a document.

Common examples:

• subskribi paperon = sign a paper
• subskribi kontrakton = sign a contract

Yes. Esperanto can express the same idea in a few ways, depending on style.

For example:

• La kuriero foriris sen mia subskribo.
  = The courier left without my signature.

This version uses a noun phrase instead of a full clause.

But the original sentence is useful because it clearly shows the action:

• La kuriero foriris sen ke mi subskribis ion.

That makes it very explicit that I did not sign anything before the courier left.

Because la means the, and Esperanto uses it much like English does.

So la kuriero means:

• the courier
• the specific courier relevant in the situation

Without la, kuriero would sound more like a courier or courier in a more general sense.

In this sentence, the speaker clearly has a particular courier in mind, so la is natural.