Kortinnehaveren må legitimere seg.

Kortinnehaveren is a compound noun:

• kort = card
• innehaver = holder / owner / possessor
• kortinnehaver = cardholder
• kortinnehaveren = the cardholder

Norwegian very often joins nouns together into one word, so where English says card holder, Norwegian usually prefers kortinnehaver.

The ending -en is the definite article attached to the noun. In English, you usually put the before the noun, but in Norwegian the definiteness is often added to the end:

• en kortinnehaver = a cardholder
• kortinnehaveren = the cardholder

So the sentence is talking about a specific cardholder, not just any cardholder.

Må means must or has to.

So:

• må legitimere seg = must identify himself/herself / must provide identification

It is the present tense of the modal verb å måtte.

A useful comparison:

• kan = can
• skal = shall / will / is supposed to
• må = must / has to

Because å legitimere seg is a reflexive expression in Norwegian. Here seg means oneself / himself / herself / themselves, depending on context.

So:

• legitimere = to identify / to authenticate / to legitimize
• legitimere seg = to identify oneself

In this sentence, seg refers back to kortinnehaveren.

This is very common in Norwegian with verbs that describe actions done to or for oneself.

Not exactly. Even though the words look related, å legitimere seg does not usually mean to legitimize oneself in everyday English.

In this context, it means something like:

• to identify oneself
• to show ID
• to prove who one is

So this is one of those cases where the most natural English translation is not the most literal one.

This is the normal word order for a main clause in Norwegian:

• Subject: Kortinnehaveren
• Finite verb: må
• Infinitive: legitimere
• Object/reflexive pronoun: seg

So the structure is:

The cardholder + must + identify + himself/herself

This is very similar to English word order in this kind of sentence.

Yes, that would be understandable, and it also means The cardholder must identify himself/herself.

However, legitimere seg is especially common in formal contexts such as:

• banks
• card use
• official checks
• security procedures

You may also see expressions like:

• vise legitimasjon = show ID
• identifisere seg = identify oneself

All are possible, but legitimere seg has a slightly formal, official tone.

Not always. Seg is a reflexive pronoun used for the third person, and the exact English translation depends on who the subject is.

Examples:

• Han må legitimere seg. = He must identify himself.
• Hun må legitimere seg. = She must identify herself.
• De må legitimere seg. = They must identify themselves.
• Kortinnehaveren må legitimere seg. = The cardholder must identify himself/herself.

So seg does not itself show gender; the subject tells you who it refers to.

Because Norwegian usually forms compound nouns by writing them as a single word.

So:

• kort
  • innehaver → kortinnehaver

This is very important in Norwegian. English often uses separate words where Norwegian uses one compound word.

Other examples:

• bankkort = bank card
• førerkort = driver’s license
• passnummer = passport number

So kortinnehaver as one word is completely standard.

Depending on context, the most natural translations would be:

• The cardholder must identify themself.
• The cardholder must show ID.
• The cardholder must provide identification.

If this appears on a machine, website, or official notice, must show ID or must provide identification is often the most natural English wording, even though the Norwegian literally says must identify oneself.