Bad Mood
Grumpy, Sullen
noun, な adjective
Remember how 機嫌 means mood? Well when you add not it becomes a bad mood. It's so bad it's like you have no mood at all.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
すぐ不機嫌になる人は嫌だ。
I don't like people who get upset easily.
そんな不機嫌そうな顔しないでさ。楽しもうよ！
Hey, don't make such a sullen face. Let's have fun!
昨日遅く寝たのに朝五時に起きなくてはいけなかったので、今日は一日中不機嫌だった。
I went to bed late last night and had to get up at five in the morning, so I was grumpy all day today.