Questions & Answers about Oppiminen on tärkeä asia.
It’s a verbal noun built from the verb oppia (to learn) + the suffix -minen, which turns a verb into a noun meaning “the act/process of X.” So oppiminen = “learning.” As a regular noun it inflects:
- nominative: oppiminen
- genitive: oppimisen
- partitive: oppimista
- elative: oppimisesta, etc.
Because the predicate is a noun phrase tärkeä asia (“an important thing”). When the predicate is a concrete noun phrase, it’s in the nominative, so the adjective tärkeä agrees with asia in nominative.
If you drop the noun and use only an adjective to describe the abstract activity, Finnish prefers the partitive: Oppiminen on tärkeää (“Learning is important”).