Abstract nouns, unlike nouns that refer to concrete things, refer to concepts or states that do not have a specific shape or color.

He is learning how to use gerunds.

What is his real name?

In Japanese grammar, the attributive form is a form that modifies nouns and adjectives.

She is learning how to use a 体言 (taigen), a noun modifier.

He chose another path.

Happiness is a mass noun, you can't count it.

The attributive form in Japanese corresponds to adjectives in English.

He is studying Japanese grammar.

He is studying Japanese.