- The definition of demented is an insane person or someone with a loss of mental function.
An example of demented is the character Dr. Frankenstein from the novel Frankenstein by Mary Shelley.
Origin of dementedpast participle of dement
- Suffering from dementia.
- Informal Crazy or foolish.
(comparative more demented, superlative most demented)
- Simple past tense and past participle of dement.