noun

1. (chiefly in the plural) An incompatible substance; one of a group of things that cannot be placed or used together because of a change of chemical composition or opposing medicinal qualities.

   “the incompatibles of iron”

2. A consequent of a contrary.

adjective

1. Of two things: that cannot coexist; not congruous because of differences

2. Incapable of being together without mutual reaction or decomposition, as certain medicines.

Synonyms: irreconcilable