Dictionary.com
Thesaurus.com
Synonyms

malformation

American  
[mal-fawr-mey-shuhn, -fer-] / ˌmæl fɔrˈmeɪ ʃən, -fər- /

noun

  1. faulty or anomalous formation or structure, especially in a living body.

    malformation of the teeth.


malformation British  
/ ˌmælfɔːˈmeɪʃən /

noun

  1. the condition of being faulty or abnormal in form or shape

  2. pathol a deformity in the shape or structure of a part, esp when congenital

"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

Other Word Forms

  • malformed adjective

Etymology

Origin of malformation

First recorded in 1790–1800; mal- + formation

Explanation

A malformation is something that doesn't have a normal shape or structure. A baby born with a heart malformation may need surgery to correct it so that her heart functions properly. Malformation is commonly used in medicine for body parts that aren't formed in the typical way. Many of these are congenital malformations, which develop before a baby is born. Frequently, malformations result in nothing more than different-looking bodies, but sometimes they're serious enough to cause problems, like a brain malformation that causes bleeding or a palate malformation that makes eating a challenge. Mal- means "bad," and here it's added to formation, "act of being formed."

Keep Reading on Vocabulary.com

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Certain pregnancies were excluded from both groups, including those that ended before 37 weeks, involved multiple babies, or resulted in a child with a major congenital malformation.

From Science Daily • Feb. 15, 2026

Congenital brain malformation researcher Patrícia Garcez and neuroscientist Stevens Rehen, who led the two projects respectively, have told the BBC they believe the answer may be a combination of these and other factors.

From BBC • Aug. 3, 2025

Its stems are curiously inclined, by a benign malformation known as fasciation, to twist and flatten into a fantail shape.

From Seattle Times • Mar. 6, 2024

Sonny was born with a congenital malformation that impaired his brain development and needs near continuous care simply to breathe and eat.

From New York Times • Mar. 4, 2024

Instead, I recited, “I have an extremely rare genetic disorder that causes malformation of the limbs.”

From "Insignificant Events in the Life of a Cactus" by Dusti Bowling