DENATURED

verb

1. To take away a natural characteristic or inherent property of (a thing or a person).
2. To add something to (alcohol) that makes it unsuitable for consumption but leaves it suitable for other purposes.
3. To alter its original form or state, especially of a protein, by heat, acidity etc.

adjective

1. Having been deprived of its nature, having had its nature changed.
2. Of alcohol made undrinkable, by adding a toxin or unpalatable substance, but still useful as a fuel or solvent. Traditionally by the addition of methanol (wood alcohol) to ethanol (grain alcohol).