Er stóllinn laus núna?

to be

Breakdown of Er stóllinn laus núna?

• núna: now
• stóllinn: the chair
• laus: loose

Questions & Answers about Er stóllinn laus núna?

Why does the sentence start with Er?

Because Icelandic makes yes/no questions by putting the finite verb first (V1 word order).
Er is the present tense of vera (to be), so Er stóllinn laus núna? is literally Is the chair free now?

What exactly is stóllinn? Why is the -inn attached?

stóllinn = stóll (chair) + the suffixed definite article -inn (the).
So stóllinn means the chair. Icelandic normally expresses the by attaching an ending to the noun rather than using a separate word.

How do I know -inn is the definite article and not just part of the noun?

You’ll see the noun without it: stóll (a chair).
The pattern is common: stóll → stóllinn (the chair). Many masculine nouns take -inn in the nominative singular definite form.

Why is it laus and not something like laust or lausir?

Adjectives agree with the noun in gender, number, and case.
Here the noun is : masculine, singular, nominative.So the adjective is masculine singular nominative: .(Neuter would typically be , plural masculine , etc.)