Using sem for Roles
In Icelandic, sem is used to mean "as" when describing a role, function, or disguise.
| On Halloween I intend to show up as a vampire. | Á hrekkjavökunni ætla ég að mæta sem vampýra. |
The role following sem must match the grammatical case of the person or thing it refers to. When the person in the role is the subject, the role is in the nominative case.
| Your sister is dressed as a beautiful angel. | Systir þín er klædd sem fallegur engill. |
| She went to the masquerade ball as a witch, but he showed up as a wizard. | Hún fór á grímuballið sem norn, en hann mætti sem galdramaður. |
Case Agreement with Objects
If the person or thing taking on the role is an object, the role must match that object's case.
For example, að klæða sig (to dress oneself) uses the accusative reflexive pronoun sig. Therefore, the costume following sem must also be in the accusative.
| The boy dressed as a zombie and used a lot of makeup. | Strákurinn klæddi sig sem uppvakning og notaði mikla förðun. |
Notice how the costume is uppvakning (accusative) rather than uppvakningur (nominative) to match sig.
| Yesterday I asked him to dress as a werewolf for the masquerade ball. | Í gær bað ég hann um að klæða sig sem varúlf fyrir grímuballið. |
The same case-matching applies when using an object "as" a substitute or painting someone "as" a character. Since the direct object is accusative, the role must be too.
| We use the red juice as blood for the vampire. | Við notum rauða safann sem blóð fyrir vampýruna. |
| I am going to paint my friend as a witch for Halloween. | Ég ætla að mála vinkonu mína sem norn fyrir hrekkjavökuna. |
Even though words like blóð and norn look identical in nominative and accusative, they are grammatically accusative here to match safann and vinkonu mína.