Learn Swedish: Barnet gav ett ilsket svar. - The child gave an angry answer.

The base form of the adjective is ilsken (angry). Because it describes the neuter noun svar (answer), it needs a neuter ending. For adjectives ending in an unstressed -en, you do not just add a -t. Instead, you replace the -n with a -t, making it ilsket.

What is the difference between ilsken and the common word arg?

While both mean angry, arg is your standard, everyday word for being mad. Ilsken is usually more intense or active, similar to irate or fiery. In this sentence, ett ilsket svar implies a sharper, more aggressive reply than just ett argt svar.

How can we tell that svar is a neuter noun here?

There are two clues in the sentence. First, it uses the indefinite article ett. Second, the adjective describing it takes the neuter ending, becoming ilsket instead of its common gender form ilsken.

What is the infinitive form of the verb gav?

The infinitive is ge (to give). It is a strong, irregular verb, so it changes its vowel in the past tense to become gav (gave).