Breakdown of Innkaupin eru hvatvís út af útsölunni.
vera
to be
út af
because of (+ dative)
innkaupið
the purchase
hvatvís
impulsive
Questions & Answers about Innkaupin eru hvatvís út af útsölunni.
Why does the adjective hvatvís look like it's in the singular form when describing the plural noun innkaupin?
Innkaup is a neuter plural noun, so the adjective must also be in the neuter plural. For many adjectives ending in -s (like hvatvís), the neuter plural form happens to be identical to the dictionary form. For comparison, the neuter singular would be hvatvíst, but the neuter plural drops the -t and goes back to hvatvís.
Is innkaup always used as a plural noun?
Yes, when it means "shopping" or "purchases" collectively, innkaup is almost always a neuter plural noun in Icelandic. This is why it takes the neuter plural definite article -in (innkaupin) and the plural verb eru.
What governs the case of útsölunni in this sentence?
The phrase út af (because of) acts as a preposition that always takes the dative case. Since útsala is a weak feminine noun, its dative form is útsölu, which becomes útsölunni once you attach the feminine dative definite article (-nni).
If I wanted to use vegna instead of út af for "because of", how would the sentence change?