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