[eyl-yuh-nist, ey-lee-uh-]


(formerly) a doctor specializing in the treatment of mental illness.
an expert witness in a sanity trial.

Origin of alienist

1860–65; alien(ation) + -ist; compare French aliéniste in same sense Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for alienist

Historical Examples of alienist

British Dictionary definitions for alienist



US a psychiatrist who specializes in the legal aspects of mental illness
obsolete a person who practises alienism
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for alienist

"one who treats mental illness, 'mad doctor,' " 1864, from French aliéniste, from alienation in the sense of "insanity, loss of mental faculty," a sense attested in English from late 15c. (see alienate).

Online Etymology Dictionary, © 2010 Douglas Harper

alienist in Medicine


[ālyə-nĭst, ālē-ə-]


A physician accepted by a court of law as an expert on the mental competence of principals or witnesses.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.