adjective Of two or more things: that cannot coexist; not congruous because of differences; unable to function together due to dissimilarities.
My phone is incompatible with the latest version of this app.
adjective Incapable of being together without mutual reaction or decomposition, as certain medicines.
noun 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.