The word un-alloyed refers to something that is pure, unmixed or without any impurities. Therefore, its antonyms are often related to impurity, mixture or contamination. Some of the antonyms for un-alloyed include adulterated, contaminated, mixed, tainted, polluted, impure, alloyed, blended, amalgamated, and impregnated. These terms are used to express that something is not completely untainted, but has some degree of impurity, mixture or contamination. For example, a person might say "the fruit juice is not un-alloyed", meaning that it has been mixed or diluted with water, sugar or other ingredients.