Hann var standandi við hurðina þegar ég kom heim.

Standandi is the present participle of standa, so it literally means standing.

In this sentence, var standandi is a descriptive way to say that he was in a standing position or in the middle of standing there.

A useful thing to know: participles in -andi are normally indeclinable, so standandi stays the same form regardless of gender, number, or case.

It is close in meaning, but not exactly the same in how Icelandic normally works.

English uses was standing as a very ordinary past continuous form. Icelandic usually does not use vera + present participle as its normal way to make a continuous tense.

So while hann var standandi is understandable and correct, Icelandic often prefers a simpler past tense form, especially with posture verbs.

In everyday speech, many speakers would more naturally say:

Hann stóð við hurðina þegar ég kom heim.

That also means He was standing by the door when I got home.

Yes, very often it would.

Stóð is the past tense of standa, and Icelandic commonly uses the simple past where English would use was standing.

So:

• Hann stóð við hurðina þegar ég kom heim = very natural, everyday wording
• Hann var standandi við hurðina þegar ég kom heim = more descriptive, a bit more marked, sometimes giving a stronger sense of the scene

So the sentence you were given is fine, but it is not the only, or always the most neutral, way to say it.

Here við means by, at, or next to.

So við hurðina means by the door or at the door.

This can be confusing for English speakers because við does not mean with in the usual companionship sense. For with a person or object, Icelandic normally uses með.

So:

• við hurðina = by the door
• með vini mínum = with my friend

Because við takes the accusative in modern Icelandic, and hurðina is the accusative singular definite form of hurð.

Breakdown:

• hurð = door
• hurðina = the door

The ending changes because Icelandic nouns show case and definiteness.

So after við, you need the accusative form:

• við hurðina = by the door

Because Icelandic usually puts the definite article onto the noun as a suffix.

So instead of a separate word like English the, Icelandic often uses an ending:

• hurð = door
• hurðin = the door, nominative
• hurðina = the door, accusative

That is why you see hurðina as one word.

Because þegar ég kom heim is a subordinate clause, and subordinate clauses usually have more straightforward word order: subject + verb.

So:

• þegar ég kom heim = when I came home

If this were a main clause, Icelandic often follows verb-second word order, but after a subordinating word like þegar, the order is normally:

• þegar + subject + verb

You can also move the whole time clause to the front:

Þegar ég kom heim, var hann standandi við hurðina.

That is also correct.

Because heim here is an adverb, not an ordinary noun phrase.

With verbs of motion, Icelandic often uses:

• fara heim = go home
• koma heim = come home

So heim means something like homeward / home.

Compare:

• ég kom heim = I came home
• ég var heima = I was at home

This is a very useful pair:

• heim = motion toward home
• heima = location at home

Because they are past tense forms, and both verbs are irregular.

• vera = to be

  • hann var = he was

• koma = to come

  • ég kom = I came

This is very common in Icelandic: many frequent verbs change their stem in the past tense.

Also notice that in the past singular, ég kom and hann kom have the same verb form. Likewise, ég var and hann var use the same past singular form.

Normally, no.

The -andi participle is usually indeclinable, so it does not change for masculine, feminine, neuter, singular, or plural.

So you can have:

• hann var standandi
• hún var standandi
• þau voru standandi

The form standandi stays the same.