Learn Finnish: Syrjäytyneet tarvitsevat parempaa kuntoutusta yhteiskunnassa. - The marginalized need better rehabilitation in society.

It acts as a nominalized adjective. Specifically, it is the plural past active participle (the "NUT participle") of the verb syrjäytyä (to become marginalized). Just like regular adjectives, Finnish participles can be used independently in the plural to represent demographic groups. Here, syrjäytyneet serves as the head of the noun phrase, meaning "the marginalized" or "marginalized people."

How does the underlying verb syrjäytyä get its meaning?

It derives from the noun syrjä, meaning "edge" or "margin". The suffix -ytyä is used to create intransitive verbs that indicate ending up in a certain state. Therefore, syrjäytyä literally means "to end up on the edge," which is the standard Finnish term for social exclusion or becoming marginalized.

Why is the object parempaa kuntoutusta in the partitive case here instead of the genitive/accusative?

The verb tarvita (to need) takes the genitive (often called the accusative) for singular, countable objects, but it requires the partitive for uncountable or abstract nouns. Because kuntoutus (rehabilitation) is an abstract, uncountable concept in this context, both the noun and its modifying comparative adjective must be in the partitive case.

Why does the comparative adjective parempi become parempaa in the partitive?