Kassinn er fullur af bókum.

to be

Breakdown of Kassinn er fullur af bókum.

• bókin: the book
• fullur: full
• af: of

Questions & Answers about Kassinn er fullur af bókum.

Why is kassinn used instead of simply kassi?

The suffix -inn is the definite article for masculine nouns in the nominative singular. Without -inn, kassi just means “a box”; with it, kassinn means “the box.”

How do you form the definite article in Icelandic for different genders and numbers?

In Icelandic, the definite article is a suffix attached to the noun’s base form: • Masculine nominative singular: -inn (kassi → kassinn)
• Feminine nominative singular: -in / -nin (bók → bókin)
• Neuter nominative singular: -ið (borð → borðið)
• Masculine nominative plural: -nir (kassar → kassarnir)
• Feminine nominative plural: -nar (bækur → bækurnar)
• Neuter nominative plural: -in (hús → húsin)

Why is the adjective fullur in its -ur form?

Adjectives agree with the noun’s gender, number, and case. Here: • kassinn is masculine nominative singular
• Predicate adjectives take the nominative case
So fullur (masc. nom. sg.) matches kassinn.