Learn Hardcore Icelandic: Kvöldið er stutt.

kvöldið is the definite singular form of kvöld, meaning the evening. Icelandic adds -ið as the neuter singular definite article suffix directly onto the noun.

Why is the adjective stutt placed after the verb er instead of before kvöldið?

Because stutt is functioning as a predicative adjective that describes the subject via the copula er. Predicative adjectives in Icelandic follow the verb and remain in their base form. To use stutt attributively (directly modifying a noun), you would say stutt kvöld, with the adjective before the noun.

Why doesn’t stutt take any endings to agree with kvöldið in gender or number?

In Icelandic, adjectives used predicatively after a form of vera (meaning to be) are not inflected. They stay in the uninflected citation form regardless of the noun’s gender, number, or case.

What case and grammatical function does kvöldið have in the sentence Kvöldið er stutt?

kvöldið is the subject of the sentence and therefore takes the nominative case. With the copular verb er, the subject always remains in nominative.