demented

/dɪˈmɛntɪd/

/dɪˈmɛntɪd/

Demented is an adjective describing behavior that is crazy, unhinged, or insane. Someone is demented when they have gone off the deep end.

Demented literally means "suffering from dementia," although in current culture it is used quite often to tease a sibling or good friend: "My brother thinks I am demented because I like to eat peanut butter and salami sandwiches."

Definitions of demented

1. adjective

   affected with madness or insanity
   synonyms: brainsick, crazy, disturbed, mad, sick, unbalanced, unhinged

   insane

   afflicted with or characteristic of mental derangement