What does denatured mean?
Denatured describes something that has been stripped of its natural properties, most often by deliberate treatment. In chemistry and industry, denatured alcohol is ethanol to which substances such as methanol have been added to make it toxic or foul-tasting, rendering it unfit for drinking and therefore exempt from beverage taxes — it is widely used as a solvent and fuel. In biochemistry, a denatured protein or nucleic acid has lost its precise three-dimensional structure, and with it its normal function, typically through exposure to heat, acids, or solvents; frying an egg is a familiar everyday example, as heat irreversibly denatures the egg's proteins. More broadly, the word can describe anything deprived of its characteristic nature or vigor. Because it belongs largely to scientific and technical writing, denatured carries a formal register, but its core idea — transformation by forceful alteration — makes it vivid even in general use.
Stripped of natural or usual qualities, especially by chemical treatment: said of alcohol made undrinkable, of proteins or nucleic acids whose structure has been disrupted, or more generally of anything altered from its natural state.
"Denatured ethanol is a cheap, effective solvent for cleaning electronics."
In everyday non-scientific use, almost always found in the phrase 'denatured alcohol'.
Past tense and past participle of 'denature': to alter the natural structure or qualities of something.
"The acid bath denatured the enzymes within seconds."
Add a poison like methanol to perfectly good ethanol and you get 'denatured alcohol' — alcohol deliberately made undrinkable so it escapes liquor taxes.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of denatured
Denatured is the past participle of the verb 'denature', formed in English from the prefix de- ('removal or reversal') combined with 'nature', which derives from Latin natura ('birth, nature, character'), itself from natus, the past participle of nasci ('to be born'). The verb arose in English around the early 19th century, first used figuratively to mean depriving something of its natural character, before acquiring its specific chemical senses later in the century. It shares the Latin root nasci with words such as innate, nativity, and cognate.
Related word forms
How denatured is actually used
Most common in technical registers — chemistry, biochemistry, and industrial contexts. Outside science, 'denatured' almost always appears in the fixed phrase 'denatured alcohol'. As a verb form ('the protein was denatured'), it is standard scientific passive usage.
Easily confused with denatured
'Denigrated' means disparaged or criticized unfairly, while 'denatured' means stripped of natural properties by treatment.