Learn Swedish: Vi importerar exklusiva olivoljor till delikatessen. - We import exclusive olive oils to the delicatessen.

This is a great example of a concept called sortpluralis (plural of kind or sort). While olja (oil) is normally an uncountable mass noun, you can pluralize it when you mean "varieties of" or "portions of" that substance. In this context, olivoljor specifically means "different types or brands of olive oil."

Why do we use the plural adjective exklusiva if oil is a mass noun?

Even though it originates from an uncountable noun, once you use the sortpluralis form (oljor), it behaves grammatically like any standard plural noun. Because of this, the adjective modifying it must take the plural -a ending, becoming exklusiva.

Since olivoljor is a compound word, which part dictates its plural ending?

In all Swedish compound words, the very last noun determines the gender (en/ett word) and the plural ending. The word is made of oliv (olive) + olja (oil). Because en olja takes the -or ending in the plural to become oljor, the entire compound becomes olivoljor.

Wait, doesn't en delikatess just mean 'a delicacy' (a fancy food item)?