名詞 dementia:

1. mental deterioration of organic or functional origin
   同義詞：dementedness

de.men.tia

n.（名詞）
Deterioration of intellectual faculties, such as memory, concentration, and judgment, resulting from an organic disease or a disorder of the brain. It is often accompanied by emotional disturbance and personality changes.
癡呆：智力能力，例如記憶力、精神集中的能力、判斷力等的惡化，常因某器官病疾或頭腦紊亂，引起經常伴隨著情感波動和性情的變化
Madness; insanity.See Synonyms at insanity
瘋狂；狂亂參見 insanity

來源：
Latin dômentia [madness]
拉丁語 dômentia [瘋狂]
from dômôns dôment- [senseless] * see dement
源自 dômôns dôment- [無知覺的] *參見 dement

【引伸】
demen.tial
adj.（形容詞）