Learn Icelandic: Ég er þreyttur og nenni ekki að daðra við þennan mann. - I am tired and do not feel like flirting with this man.

While vilja simply means to want, nenna specifically refers to having the energy, motivation, or patience to do something. Saying ég nenni ekki translates well to "I can't be bothered" or "I don't have the energy for it." This pairs perfectly with the first half of the sentence where the speaker states ég er þreyttur (I am tired).

Since nenna acts somewhat like a modal verb here, why do we need að before daðra?

Although nenna (to be bothered) and þora (to dare) express mental dispositions similar to modal verbs, they do not share their exact grammar. True modal verbs like vilja or skulu take a bare infinitive, but nenna and þora act like regular verbs and always require the infinitive marker að before the next verb.

Why is the phrase við þennan mann in the accusative case?

The verb daðra (to flirt) pairs with the preposition við. When við is used to express interaction or communication with someone, it dictates the accusative case. Because of this, both the demonstrative pronoun þennan and the noun mann take the masculine accusative form.

Does the form of the word þreyttur tell us anything about the speaker?