Nightmare
Bad Dream
noun
A bad dream is also known as a nightmare. Ah! Noooooo!
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
夜中に悪夢で目が覚めました。
I woke up in the middle of the night with a nightmare.
昨日、悪夢にうなされてたよ。
Yesterday, you were groaning from a nightmare.
まるで悪夢を見ているようでした。
It was like having a nightmare.