Mood
Temper
noun
Machines dislike everything. Their mood, or temper, is very sour. What about your mood?
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. けん gets changed to げん, though, so don't let that ruin your mood.
コウイチは、機械のように、毎日三時のおやつの時間になると機嫌が良くなる。
Koichi gets in a good mood for three o'clock snack time, every day like clockwork.
今日のお母さんの機嫌はどう？
What kind of mood is mom in today?
「彼女は朝、機嫌が悪いわね。」「ええ、全くその通りね。」
"Her mood's terrible in the morning." "Yeah don’t I know it!"