ADULTERANT
adulterating, adulterant
(adjective) making impure or corrupt by adding extraneous materials; “the adulterating effect of extraneous materials”
adulterant, adulterator
(noun) any substance that lessens the purity or effectiveness of a substance; “it is necessary to remove the adulterants before use”
Source: WordNet® 3.1
Noun
adulterant (plural adulterants)
That which adulterates, or reduces the purity of something.
Source: Wiktionary
A*dul"ter*ant, n. Etym: [L. adulterans, p. pr. of adulterare.]
Definition: That which is used to adulterate anything.
– a. Adulterating; as, adulterant agents and processes.
Source: Webster’s Unabridged Dictionary 1913 Edition