Translation guide
Describes someone whose emotions change frequently or unpredictably. Japanese has several expressions, from clinical terms to casual slang, often focusing on mood swings, temperament, or being easily affected by circumstances.
Describing a person whose mood changes often and unpredictably, sometimes in a negative or difficult way.
A common, slightly negative term for someone whose mood changes easily, often used for people who are hard to deal with because of their moodiness.
He's moody, so you'd better not talk to him today.
Literally 'has uneven moods', a descriptive phrase for someone whose mood fluctuates.
She's moody and it's tiring to be around her.
Refers to manic-depressive or bipolar tendencies. Clinical and strong; use carefully.
a person with manic-depressive tendencies
Describing a person who is quick to anger or irritation, often over small things.
Describing a person whose emotional state is easily influenced by what's happening around them, like weather or small events.
Informal ways to call someone moody, often used among younger people.
Slang derived from 'mental health', often used online to describe someone emotionally unstable or attention-seeking. Can be derogatory.
Can be offensive; avoid in polite conversation.
That girl seems a bit moody/mentally unstable.
There is no single Japanese word that perfectly matches 'moody person'. Using ムーディーな人 (moody person) would be understood as 'atmospheric' or 'romantic', not emotionally unstable.
気分屋 emphasizes changing moods (happy to sad), while 短気 emphasizes a quick temper. Choose based on whether the moodiness is about emotional variability or irritability.
Lately, he's become moody and irritable.
It's tough to be in a relationship with someone who has intense mood swings.