What does flaw mean?
A flaw is a fault or imperfection — a defect that undermines the quality, integrity, or soundness of something. The word applies across a remarkable range of contexts: to physical objects (a hairline flaw in a gemstone, a manufacturing flaw in an aircraft part), to abstract creations (a flaw in a legal contract, a design flaw in software, a logical flaw in an argument), and to human beings themselves, where a character flaw denotes a weakness such as jealousy or pride. This breadth makes flaw one of English's most versatile evaluative words, useful whenever something falls short of what it should be. Its connotations vary accordingly: in engineering and law, flaws are serious problems demanding correction, while in literature and psychology they are often treated sympathetically, since imperfection is understood as an essential part of human nature. Curiously, the word traces back not to any notion of judgment but to Old Norse, where it originally meant a slab or chip of stone. Related derivatives include the ubiquitous adjectives 'flawed' and 'flawless', and the phrase 'fatal flaw' has become shorthand for the single weakness that brings down an otherwise strong plan, argument, or hero.
A fault, defect, or imperfection in a physical object, an abstract creation such as a plan or argument, or a person's character.
"The auditors uncovered a fundamental flaw in the company's accounting."
Commonly paired with phrases like 'fatal flaw', 'character flaw', and 'design flaw' depending on context.
To introduce a flaw into something; to crack, damage, or render defective.
"Years of frost had flawed the surface of the marble steps."
This verb use is uncommon today; the far more frequent expression is the derived adjective 'flawed', as in 'a flawed argument'.
The plural is standard and used freely when referring to multiple defects, e.g. in inspections, reviews, or critiques.
"Despite its many flaws, the manuscript was accepted for publication."
The word for 'imperfection' itself began as a chip of stone — it comes from an Old Norse word meaning a slab of flagstone, before evolving into the term we now use for cracks in diamonds and defects in heroes.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of flaw
Flaw derives ultimately from Old Norse, specifically from a word related to 'flaga', meaning a flat slab or flagstone. It entered English around the early sixteenth century, its earliest recorded senses concerning chips or splinters — including flakes cut from turf or stone. Over time the sense narrowed and shifted: by the seventeenth century the word had come to mean a crack or fissure, particularly one in a gemstone, and from there it generalized naturally to mean any defect or imperfection. It shares this Norse origin with words such as 'flake' and 'flag'.
Related word forms
How flaw is actually used
Flaw is neutral in register, appearing equally in everyday conversation and technical writing. Its connotation depends on context: in materials and objects it suggests a defect to be detected or repaired, while applied to people it usually carries a sympathetic, humanizing tone — a character flaw implies imperfection rather than outright vice. The adjective forms 'flawed' and 'flawless' are extremely common, and the phrase 'fatal flaw' is widely used both in literary criticism and in discussions of plans and arguments.
Easily confused with flaw
Flow refers to smooth, continuous movement or motion, whereas flaw refers to a defect or imperfection; the two differ by only one letter but have entirely unrelated meanings.
Floor is the surface of a room or a minimum level, while flaw is an imperfection or defect.