happy mood; euphoric mood
Describes a light, cheerful, almost giddy state of happiness. Often used in casual contexts.
Today was payday, so I went home in a happy mood.
Wearing her new dress, she headed to the party in a euphoric mood.
Standard spelling with katakana for the mimetic part and kanji for 気分.
Hiragana variant; less common but still seen.
ルンルン is a mimetic word representing a light, happy humming or singing feeling. Combined with 気分 (mood), it forms a set phrase meaning a euphoric mood. The exact origin of ルンルン is uncertain, but it likely imitates a cheerful tune or sound.