恐ろしい
おそろしい · osoroshii · JLPT N3 · i-adj
terrible
👻 恐 = fear: osoru (to fear) + -shii makes it fear-inducing, so terrible
The kanji 恐 means fear, as in 恐怖 (kyōfu, terror). Add the adjective ending -shii to the old verb osoru (to fear) and you get osoroshii: something that makes you afraid. Sound hook: oh, so horrible-ish!