derangement

1 a serious mental disorder that prevents one from living a safe and normal life given powerful drugs to treat his derangement Synonyms aberration, dementia, insanity, lunacy, madness, mania, rage [archaic]Related Words neurosis, psychosis; instability, irrationality, unreasonableness; delirium, frenzy, hysteria; hallucinosis, hypomania, paranoia, schizophrenia; senile dementia; delusion, hallucination; monomania, obsession, phobia; abnormality, dementedness, unsoundnessNear Antonyms lucidity, rationality, rationalness, reasonability, reasonableness; normality, soundnessAntonyms mind, saneness, sanity

2 an act or instance of the order of things being disturbed the derangement of the carefully organized event by a single freak accident Synonyms upset, dislocation, disruption, disturbanceRelated Words convulsion, revolution, unsettledness, unsettlement, upheaval