Learn Icelandic: Hún hatar bókhaldið en elskar markaðssetninguna. - She hates the accounting but loves the marketing.

In Icelandic, it is very common to use the definite article for general concepts, fields of study, or abstract nouns when talking about them as a whole. While English says "She hates accounting," Icelandic says Hún hatar bókhaldið (literally "the accounting").

What gender and case is markaðssetninguna?

It is a feminine noun in the accusative case. The base word is markaðssetning. Because the verb elskar requires its object to be in the accusative, the attached definite article takes the accusative feminine form -una.

How is the compound word markaðssetning built?

It is formed from markaður (market) and setning (setting or placing). They are joined by an -s-, which is the genitive ending of markaður, giving it the literal meaning of "placing of a market."

This lesson is about eigin (own). How would I say she hates "her own accounting" in this sentence?

You would say Hún hatar sitt eigin bókhald. You must use the reflexive possessive sitt (neuter accusative) because it refers back to the subject, Hún. Notice that bókhald loses its definite article here, because words following possessive pronouns and eigin do not take the attached article.