ákveðins

Ákveðins is a grammatical inflection of the Icelandic adjective ákveðinn, meaning "definite" or "certain." In Icelandic grammar, adjectives agree with the nouns they modify for gender, number, and case, and the definite forms comprise a set of endings used with definite noun phrases. Ákveðins is the genitive singular form of ákveðinn and is used when the modified noun is in the genitive case. The form is most commonly encountered in written, formal Icelandic, including historical texts, legal language, and lexicography; it is less frequent in everyday speech, where speakers often use other constructions to convey definiteness.

Etymology: The adjective ákveðinn derives from the verb ákveða, "to determine" or "to decide." The genitive singular form ákveðins reflects the broader Icelandic pattern of adjective inflection, where the ending -ins marks genitive singular for masculine nouns (and, in some contexts, for neuter as well). The sense of the word has remained “definite,” “particular,” or “certain” through its history.

Usage notes: Ákveðins marks a genitive relationship, so it typically appears in phrases indicating possession or in contexts requiring grammatical case agreement in writing. It is not used as a predicative adjective and is uncommon in casual spoken Icelandic, where simpler constructions are preferred.