loka ("to close, to shut") looks like the most ordinary verb in the world — a regular weak Class-1 verb with an -aði past — and then it does something that surprises every learner: it takes its object in the dative, not the accusative. You close the door with the door in the dative: loka hurðinni. Its opposite, opna "to open," takes the accusative. This asymmetric pair is one of the most-cited oddities of Icelandic grammar, and learning loka properly means learning to feel that dative.
Conjugation
Class: weak, Class 1 (the -aði preterite). Auxiliary: hafa — ég hef lokað "I have closed."
| Principal parts | |
|---|---|
| Infinitive | að loka |
| 3sg present | lokar |
| 3sg past | lokaði |
| Supine | lokað |
| Person | Present (nútíð) | Past (þátíð) |
|---|---|---|
| ég | loka | lokaði |
| þú | lokar | lokaðir |
| hann / hún / það | lokar | lokaði |
| við | lokum | lokuðum |
| þið | lokið | lokuðuð |
| þeir / þær / þau | loka | lokuðu |
| Person | Present subjunctive | Past subjunctive |
|---|---|---|
| ég | loki | lokaði |
| þú | lokir | lokaðir |
| hann / hún / það | loki | lokaði |
| við | lokum | lokuðum |
| þið | lokið | lokuðuð |
| þeir / þær / þau | loki | lokuðu |
| Non-finite & imperative | |
|---|---|
| Imperative (þú) | lokaðu |
| Imperative (þið) | lokið! |
| Supine | lokað |
| Past participle / adjective (m/f/n) | lokaður / lokuð / lokað — "closed, shut" |
| Middle voice (miðmynd) | lokast — "to close (by itself), to shut" |
loka + dative — the case surprise
Most transitive verbs take the accusative, so a learner's default for "close the door" is loka hurðina. That is wrong: loka assigns the dative. The thing you close goes into the dative — hurðinni (the door), glugganum (the window), dyrunum (the doors), bókinni (the book).
Lokaðu hurðinni, það er dragsúgur.
Close the door, there's a draught.
Ég lokaði glugganum af því að það byrjaði að rigna.
I closed the window because it started to rain.
Manstu eftir að loka bílnum?
Did you remember to lock the car? (lit. close the car — dative bílnum)
There is no neat semantic reason "open" takes the accusative while "close" takes the dative — it is simply how these two verbs are lexically marked, and you must memorise it. loka belongs to a sizeable group of dative-governing verbs (loka, ljúka, breyta, hætta, henda); the case is a property of the verb, not predictable from the meaning.
No u-umlaut — lokum, not lökum
Just like opna, the stem vowel of loka is o, and o never takes the u-umlaut. So "we close" is lokum, never lökum, and the past plural is lokuðum / lokuðu, never lökuðum. Only short a umlauts to ö.
lokast — "close by itself"
When something shuts on its own — a door swings closed, an app closes, a road is closed off — use the middle voice lokast. The thing that closes becomes the subject, and there is no one doing the closing.
Hurðin lokaðist með háum smelli.
The door closed with a loud click.
Verslunin lokast klukkan sex.
The store closes at six.
Contrast the active and middle: ég loka búðinni = I close the shop (I am the agent; búðinni dative); búðin lokast = the shop closes (it shuts, no agent; búðin nominative). Note that the agent's object is dative, but the middle-voice subject is nominative.
lokaður — "closed" (the adjective)
The past participle lokaður / lokuð / lokað is used as an everyday adjective meaning "closed/shut," and as the sign on a door it is simply Lokað.
Búðin er lokuð á sunnudögum.
The shop is closed on Sundays. (búðin is feminine → lokuð)
Vegurinn er lokaður vegna snjóa.
The road is closed due to snow.
Common Mistakes
❌ Lokaðu hurðina.
Incorrect — loka takes the DATIVE, so it must be hurðinni, not the accusative hurðina
✅ Lokaðu hurðinni.
Close the door.
❌ Við lökum glugganum.
Incorrect — the stem vowel o never takes u-umlaut; 'we close' is lokum
✅ Við lokum glugganum.
We're closing the window.
❌ Búðin lokaði klukkan sex.
Incorrect — a shop closing by itself needs the middle voice lokast; the active lokaði needs an agent and a dative object
✅ Búðin lokast klukkan sex.
The shop closes at six.
❌ Ég lokdi bókinni.
Incorrect — loka is an -aði verb, not a -di verb; the past is lokaði
✅ Ég lokaði bókinni.
I closed the book.
Key Takeaways
- loka / lokar / lokaði / lokað — a regular weak Class-1 verb (-aði past).
- It takes its object in the DATIVE (loka hurðinni, loka glugganum) — the mirror image of opna
- accusative.
- No u-umlaut: the stem vowel o stays put — "we close" is lokum, past plural lokuðum / lokuðu.
- The middle voice lokast means "to close by itself" (búðin lokast klukkan sex), with a nominative subject.
- The participle lokaður / lokuð / lokað ("closed") is the door sign Lokað.
- Imperative lokaðu; auxiliary hafa (ég hef lokað).
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- opna (to open)A2 — Full conjugation of the weak Class-1 verb opna (opna / opnaði / opnað), which takes an ACCUSATIVE object (opna hurðina), the anticausative middle opnast ('open by itself'), and why its o-stem does NOT take the u-umlaut (opnum, not öpnum).