idiosyncrasy

noun

id·​i·​o·​syn·​cra·​sy ˌi-dē-ə-ˈsiŋ-krə-sē 

plural idiosyncrasies

1

a

: a peculiarity of constitution or temperament : an individualizing characteristic or quality

b

: individual hypersensitiveness (as to a drug or food)

2

: characteristic peculiarity (as of temperament)

broadly : eccentricity

idiosyncratic

ˌi-dē-ō-(ˌ)sin-ˈkra-tik 

adjective

idiosyncratically

ˌi-dē-ō-(ˌ)sin-ˈkra-ti-k(ə-)lē 

adverb

Synonyms

• trick
• trait
• characteristic
• quirk
• mannerism
• peculiarity
• eccentricity
• habit
• individualism
• oddity
• singularity
• curiosity
• tic

Examples of idiosyncrasy in a Sentence

Her habit of using “like” in every sentence was just one of her idiosyncrasies.

The current system has a few idiosyncrasies.

Recent Examples on the Web

All of Parker’s records have a particular idiosyncrasy, a wobble, a beat that’s not beating. —Amanda Petrusich, New Yorker, 17 Oct. 2025

Candidates familiar with Preller’s idiosyncrasies might have an early advantage. —Dennis Lin, New York Times, 15 Oct. 2025

Benicio Del Toro made a surprise cameo appearance on Saturday Night Live tonight, joining host Bad Bunny and frequent collaborator Marcello Hernandez in a sketch spoofing the idiosyncrasies of the Spanish language. —Natalie Oganesyan, Deadline, 4 Oct. 2025

Each character is set up simply, but as the narrative builds, so do their idiosyncrasies. —Holly Jones, Variety, 26 Sep. 2025

Word History

Etymology

Greek idiosynkrasia, from idio- + synkerannynai to blend, from syn- + kerannynai to mingle, mix — more at crater

First Known Use

1604, in the meaning defined at sense 1a

Rhymes for idiosyncrasy

• ethylenediamine
• nanotechnology
• phenomenology
• phenylenediamine
• abc
• absentee
• addressee
• adoptee
• agouti
• allottee
• amphorae
• amputee

Kids Definition

idiosyncrasy

noun

id·​io·​syn·​cra·​sy

ˌid-ē-ə-ˈsiŋ-krə-sē

plural idiosyncrasies

: a way of behaving or thinking that is characteristic of a person

idiosyncratic

ˌid-ē-ō-(ˌ)sin-ˈkrat-ik

adjective

idiosyncratically

-ˈkrat-i-k(ə-)lē

adverb

Medical Definition

idiosyncrasy

noun

id·​io·​syn·​cra·​sy ˌid-ē-ə-ˈsiŋ-krə-sē 

plural idiosyncrasies

1

: a peculiarity of physical or mental constitution or temperament

2

: individual hypersensitiveness (as to a drug or food)

anemia accompanying the use of a sulfa drug is usually considered to be due to idiosyncrasy