Siskoni meni turvatarkastukseen ilman että hän otti veden pois käsimatkatavarasta.

Siskoni means my sister.

Finnish often shows possession by adding a possessive suffix to the noun:

• sisko = sister
• siskoni = my sister

The suffix -ni means my.

You can also say minun siskoni, but that is more explicit or emphatic. Very often, just siskoni is enough.

Because the sentence uses the verb mennä (to go), and Finnish usually marks the destination with a case ending.

Here:

• turvatarkastus = security check / security screening
• turvatarkastukseen = into/to the security check

This is the illative case, which often expresses movement into or to something.

So:

• mennä turvatarkastukseen = to go to security

This is very natural Finnish.

The base word is turvatarkastus.

Words ending in -us often change their stem before endings are added:

• turvatarkastus
• stem: turvatarkastukse-
• illative ending: -en
• result: turvatarkastukseen

So even though it may look complicated, it is a normal case form of a noun ending in -us.

Ilman että means without (someone) doing something.

It introduces a whole clause:

• ilman että hän otti veden pois käsimatkatavarasta
• without her taking the water out of the carry-on luggage

This is a very common Finnish structure when you want a full clause with its own verb.

A rough literal breakdown is:

• ilman = without
• että = that

But you should learn ilman että as a fixed expression meaning without doing / without someone doing.

Because the main sentence is in the past:

• meni = went

The action in the ilman että clause is also understood in relation to that past event, so Finnish uses the past there too:

• otti = took

So the sentence describes a past situation:

• she went through/to security
• without taking the water out

Using ottaa here would not work, because that is the basic dictionary form, not a finite verb for the clause.

In this sentence, hän means she and makes the subordinate clause fully explicit:

• ilman että hän otti...

That is completely normal.

Finnish often leaves subjects out only when the verb ending already clearly shows the person, but here otti is a third-person past form and does not by itself tell you whether the subject is he, she, or it. So hän helps keep the meaning clear.

Also, with ilman että, using an explicit subject is very natural.

This is about the object case.

• vesi = water (basic dictionary form)
• veden = water, as a total object
• vettä = water, as a partial object

In otti veden pois, the water is treated as a whole item that was supposed to be removed. That is why veden is used.

A useful contrast:

• hän joi vettä = she drank some water
• hän joi veden = she drank the water / all the water

Here, veden suggests a specific amount or item, for example a bottle of water or the water as a single thing that should have been removed.

Pois means something like away or out.

With ottaa, it often creates the meaning take away or remove:

• ottaa = take
• ottaa pois = take away / remove

So:

• otti veden pois käsimatkatavarasta
• took the water out of the carry-on luggage

You might sometimes hear Finnish without pois, but here pois makes the idea of removal especially clear and natural.

Because the ending -sta means out of / from.

• käsimatkatavara = carry-on luggage / hand luggage
• käsimatkatavarasta = out of the carry-on luggage

This is the elative case, which often expresses movement out of something.

So the phrase:

• pois käsimatkatavarasta

means:

• out of the carry-on luggage

It is singular in form:

• käsimatkatavara = carry-on luggage / carry-on item

Finnish often uses a singular form where English might use an uncountable expression like luggage.

So käsimatkatavarasta can naturally mean:

• out of the carry-on luggage
• out of the carry-on bag
• out of her hand luggage

If you wanted to emphasize multiple carry-on items, you could use a plural form, but the singular is perfectly normal here.

Yes. Finnish often uses a non-finite form instead of ilman että.

For example, a more compact version could be:

• Siskoni meni turvatarkastukseen ottamatta vettä pois käsimatkatavarasta.

Here ottamatta means without taking.

Both structures are correct, but they feel slightly different:

• ilman että hän otti... = full clause, very explicit
• ottamatta... = more compact, often smoother

A learner will often meet both patterns, so it is useful to recognize them both.

Because ilman että already contains the idea of absence: without.

So standard Finnish says:

• ilman että hän otti...

not:

• ilman että hän ei ottanut...

The negative meaning is already built into ilman. Adding ei would usually be wrong here in standard Finnish.

So think of it as:

• without her taking...

not:

• without her not taking...

Not completely. Finnish word order is fairly flexible, but this sentence uses a very neutral, natural order:

• Siskoni = subject
• meni = verb
• turvatarkastukseen = destination
• ilman että... = subordinate clause

This is a straightforward way to present the information.

You could change the order for emphasis, but the given version is a good standard model for learners.