AskDefine | Define idiosyncrasy

Dictionary Definition

idiosyncrasy n : a behavioral attribute that is distinctive and peculiar to an individual [syn: foible, mannerism]

User Contributed Dictionary



First attested in 1604, in modern sense since 1665, from idiosyncrasie < sc=polytonic < sc=polytonic + sc=polytonic + sc=polytonic.


  • /ˌɪd.i.əʊˈsɪŋ.krə.si/, /%Id.i.@U"
  • /ˌɪdi.əˈsɪŋkɹəsi/


  1. A way of behaving or thinking that is characteristic of a person.
  2. A language or behaviour that is particular to an individual or group.
  3. A peculiar individual reaction to a generally innocuous substance or factor.
  4. A peculiarity that serves to distinguish or identify.
    He mastered the idiosyncrasies of English spelling.
way of behaving or thinking
language or behaviour particular to an individual or a group
individual reaction to a generally innocuous substance
a peculiarity that serves to distinguish or identify
  • Danish: særhed
  • German: Eigenheit, Eigenart

Extensive Definition

Idiosyncrasy, from Greek ιδιοσυγκρασία, idiosunkrasia, "a peculiar temperament", "habit of body" (idios "one's own" and syn-krasis "mixture"). It is defined as an individualizing quality or characteristic of a person or group, and is often used to express eccentricity or peculiarity. The term can also be applied to symbols. Idiosyncratic symbols mean one thing for a particular person, as a blade could mean war, but to someone else, it could symbolize a surgery. By the same principle, linguists state that words are not only arbitrary, but also largely idiosyncratic signs.

Idiosyncrasy in medicine


Idiosyncrasy defined the way physicians conceived diseases in the nineteenth century. They considered each disease as a unique condition, related to each patient. This understanding began to change in the 1870s, when discoveries made by researchers in Europe permitted the advent of a 'scientific medicine', a precursor to the Evidence-Based Medicine that is the standard of practice today.


In contemporary medicine (as of 2007), the term Idiosyncratic drug reaction denotes a non-immunological hypersensitivity to a substance, without connection to pharmacological toxicity.. Idiosyncratic stresses here the fact that other individuals would react differently, or not at all, and that the reaction is an individual one based on a specific condition of the one who suffers it. Most commonly, this is caused by an enzymopathy, congenital or acquired, so that the triggering substance cannot be processed properly in the organism and causes symptoms by accumulating or blocking other substances to be processed. An idiosyncrasy causing symptoms like an allergy is also called pseudoanaphylaxis .


In psychiatry, the term means a specific and unique mental condition of a patient, often accompanied by neologisms. In psychoanalysis and behaviorism, it is used for the personal way a given individual reacts, perceives and experiences a common situation: a certain dish made of meat may cause nostalgic memories in one person and disgust in another. These reactions are called idiosyncratic.

Idiosyncrasy in economics

In portfolio theory, risks of price changes due to the unique circumstances of a specific security, as opposed to the overall market, are described as idiosyncratic risk. This risk can be virtually eliminated from a portfolio through diversification. It is also often called unsystematic or specific risk. It means there is no compensation for risk, no matter how risky the asset is, and no matter how risk averse we are.
In econometrics, idiosyncratic error is used to describe error from panel data that both changes over time and across units (individuals, firms, cities, etc.)


idiosyncrasy in Bulgarian: Идиосинкразия
idiosyncrasy in Danish: Idiosynkrasi
idiosyncrasy in German: Idiosynkrasie
idiosyncrasy in Spanish: Idiosincrasia
idiosyncrasy in French: Idiosyncrasie
idiosyncrasy in Italian: Idiosincrasia
idiosyncrasy in Dutch: Idiosyncrasie
idiosyncrasy in Polish: Idiosynkrazja (psychologia)
idiosyncrasy in Portuguese: Idiossincrasia
idiosyncrasy in Russian: Идиосинкразия
idiosyncrasy in Swedish: Idiosynkrasi
idiosyncrasy in Ukrainian: Ідіосинкразія

Synonyms, Antonyms and Related Words

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