senile
adj. 高龄的;老衰的;高龄所致的
例句
I think she's going senile.
我想她是衰老了。
《牛津词典》
She is suffering from senile dementia.
她受老年痴呆症折磨。
《柯林斯英汉双解大词典》
It tottered on the borders of senile decay.
它在衰老的边缘摇摇欲坠。