Learn Hardcore Icelandic: Maðurinn er reiður.

In Icelandic, nouns usually attach the definite article to the end instead of having a separate word. The base form maður means "man," but adding -inn makes it maðurinn, which translates to the man.

Why is the adjective reiður used here instead of another form like reið or reiður with a different ending?

Icelandic adjectives must agree in gender, number, and case with the noun they describe. Here, maðurinn is masculine singular nominative, so the adjective also appears in its masculine singular nominative form: reiður.

Does er simply mean is, similar to English?

Yes, er is the third-person singular present form of the verb vera (to be). In this context, it’s equivalent to is in English.

How would the sentence change if I wanted to say "The woman is angry"?

You would change maðurinn (the man) to konan (the woman) and adjust the adjective form if needed. So it becomes Konan er reið. Notice that reið is the feminine form of the adjective meaning angry.

Is it common to omit the subject pronoun in Icelandic, as in other languages?

No, Icelandic usually includes the subject unless it's implied in another way. You normally say Maðurinn er reiður rather than just er reiður. The verb ending in Icelandic doesn’t change with each pronoun the way it does in some languages like Spanish or Italian, so you typically need the subject to clarify who or what is being described.