Other forms: deranged, deranging
To derange is to drive somebody out of their right mind. Deranged by grief, a deranged look, utterly deranged.
The participle is the only form in common use, and deranged is now a lay word rather than a clinical one, since psychiatry abandoned it long ago. The French behind it simply means to throw out of order.
1verbderangeTo drive somebody out of their right mind.
“Years of isolation in the lighthouse seemed to derange the old keeper.”
derange is a maddening.
French deranger means to throw into disorder, from des- plus rengier, to put into line.
Old French
desrengier — throw into disorder
French
déranger
English, today
derange
Built from
From French déranger, from Old French desrengier (“throw into disorder”), from des- + rengier (“to put into line”), from reng (“line, row”), from a Germanic source. See rank (noun).
Etymology from Wiktionary, CC BY-SA