Unadulterated means pure, with nothing added and nothing taken away. Unadulterated joy, unadulterated nonsense, pure and unadulterated.
The figurative use is much the commoner and works for good and bad alike, since unadulterated joy and unadulterated rubbish are equally natural. The literal sense belongs to food law, where adulteration is a named offence.
1adjectiveunadulteratedPure, with nothing added and nothing taken away.
“The shop sells unadulterated olive oil straight from the farm.”
unadulterated is a quality.
From un- + adulterated.
Etymology from Wiktionary, CC BY-SA