Learner's definition of DEMENTED
[more demented; most demented]
not able to think clearly or to understand what is real and what is not real
crazy or insane
Many of the patients there were demented.
In the movie, he plays a demented man trying to survive on the streets of Los Angeles.
Her demented ramblings are a symptom of her illness.
He gave me a demented little smile.
parents who are almost demented with worry