nauðsynlegu

Nauðsynlegu is a form of the Icelandic adjective nauðsynlegur, which means "necessary" or "essential." It is used to describe nouns as required or indispensable and appears as one of the many inflected endings the Icelandic adjective can take to agree with gender, number, and case.

Etymology and related forms: The word derives from nauðsyn, meaning "need" or "necessity," combined with the common adjectival suffix -legur. The base nauðsynlegur has several inflected variants such as nauðsynlegt (neuter), nauðsynleg (feminine or in certain forms), and nauðsynlegi (definite masculine form), with nauðsynlegu representing another inflected variant used in particular grammatical contexts.

Grammatical notes: Icelandic adjectives agree with the nouns they modify in gender, number, and case. The ending -u in nauðsynlegu is one example of how an adjective can change to fit a sentence’s syntactic role. The exact form depends on the noun’s gender, whether it is definite, and the sentence’s case. Learners typically consult a grammar table to match the correct ending to a given noun phrase.

Usage: The most common, non-inflected sense is expressed by nauðsynlegur (masculine), nauðsynlegt (neuter), and nauðsynleg (feminine) in everyday speech and writing. Nauðsynlegu tends to appear in formal, literary, or specific syntactic contexts where its particular inflection is required.

See also: nauðsynlegur, nauðsynlegt, Icelandic grammar, adjective agreement.