na-adjective, noun
mediocre; inferior; commonplace; foolish
Rare literary term for something or someone of low quality, mediocre, or foolish. Not used in everyday speech.
彼の作品は庸劣で、評価に値しない。
His work is mediocre and not worth evaluating.
庸劣な考えに惑わされてはいけない。
Don't be misled by foolish ideas.