Questions & Answers about Planinarenje je zabavno.
Because planinarenje is a neuter singular noun, and the adjective zabavno agrees with it.
In Serbian, predicate adjectives after je usually match the noun in gender and number:
- zabavan = masculine singular
- zabavna = feminine singular
- zabavno = neuter singular
- zabavni / zabavne = plural forms, depending on context
So:
- Film je zabavan. = The film is fun.
- Igra je zabavna. = The game is fun.
- Planinarenje je zabavno. = Hiking is fun.
It is a noun, even though it refers to an activity.
Planinarenje means hiking / mountaineering / the activity of going in the mountains. It is formed like many Serbian activity nouns in -nje or -anje, which often correspond to English -ing forms.
So in this sentence, planinarenje behaves grammatically like a noun, not like a verb.
Je is the 3rd person singular present tense of biti = to be.
So the structure is: