Kyūjitai form of 体系: system; organization

an immune system

visual kei

aggressive in relationships

(slang) denpa-kei person: one who acts strangely (disconnected from reality), often having wild fantasies and often saying strange things

a nervous system

A person not interested in marriage or dating; a person who is considered insufficiently assertive / A man deemed insufficiently masculine or manly

Alternative form of ヴィジュアル系 (vijuaru-kei)

that which can warm one's heart, calm one's mind and provide comfort in times of sadness

dynamical system