idiosyncrasy

plural idiosyncrasies

1. A behavior or way of thinking that is characteristic of a person or a group.

   Every village has its idiosyncrasy, its constitution, often its own code of morality.

   1891, Thomas Hardy, Tess of the d’Urbervilles: A Pure Woman Faithfully Presented […], volume (please specify |volume=I to III), London: James R[ipley] Osgood, McIlvaine and Co., […], →OCLC

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   This mode of death had been an idiosyncrasy with his family, for generations past; not often occurring, indeed, but, when it does occur, usually attacking individuals about the Judge’s time of life, and generally in the tension of some mental crisis, or, perhaps, in an access of wrath.

   1851 April 9, Nathaniel Hawthorne, The House of the Seven Gables, a Romance, Boston, Mass.: Ticknor, Reed, and Fields, →OCLC

   If he expresses himself such as he is, an idiosyncrasy affected but not annihilated by education, he may say that his books are his own.

   1898 [1884], Philip Gilbert Hamerton, “Independence”, in Human Intercourse

   She's flying in from Stockholm on Thursday. She apparently has certain sexual idiosyncrasies.

   1980, Paul Schrader, American Gigolo, spoken by Anne (Nina van Pallandt)

   When we situate climax during intercourse as the bullseye, we gate off the idiosyncrasy and experimentation that are the wellspring of sexual pleasure.

   2023 March 21, Zoe Williams, “The orgasm gap – and how to close it: ‘Don’t equate sex and penetration’”, in The Guardian, archived from the original on 31 Mar 2023

   The trouble with this question is that it removes the focus from the substance of whatever event or debate is being discussed, redirecting it to the speaker’s or writer’s personal perceptions or expectations about it — away from facts and toward idiosyncrasy.

   2026 January 1, Carlos Lozada, “How Did We Get to Such a Bad Question?”, in The New York Times, New York, N.Y.: The New York Times Company, →ISSN, →OCLC, archived from the original on 02 Jan 2026

   Synonyms: eccentricity, foible, habit, idiocrasy, mannerism, oddity, quirk, vagary

2. originallymedicineA peculiar individual reaction to a generally innocuous substance or factor; a risk factor.

   […]I have no antipathy, or rather Idio-ſyncraſie, in dyet, humour, ayre, any thing; […].

   1642, [Thomas Browne], “The Second Part”, in Religio Medici, London: […] Andrew Crooke, →OCLC, page 111

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   There are, however, distinct differences between diatheses and idiosyncrasies; diatheses definitely tend to the development of disease, for example the scrofulous diathesis of our forebears favours the onset of tuberculosis; idiosyncrasies are abnormal reactions but do not necessarily dispose to disease.

   1927, Humphry Davy Rolleston, Idiosyncrasies, London: Kegan Paul, pages 16–17

3. A peculiarity that serves to distinguish or identify.

   He mastered the idiosyncrasies of English spelling and speech.