Learn Icelandic: Við þurfum sokka núna.

The verb þurfa (to need) always forces the thing being needed into the accusative case. Because we are stating what we need, the word for socks becomes the direct object.

Why does sokka end in -a?

Sokka is the accusative plural form of the masculine noun sokkur (sock). In the plural, many masculine nouns drop the -ar ending used for the subject (nominative) and replace it with -a when they are the object (accusative).

How would this sentence look if we needed THE socks?

It would be Við þurfum sokkana núna. To make a masculine accusative plural noun definite (meaning "the"), you attach the ending -na to the bare accusative form sokka.

Is there a difference between nú and núna?

Yes! While both mean "now", núna usually means "right now" at this very moment. Nú is a bit broader and can refer to the current time period in general. Since the need for socks is immediate here, núna is a great fit.