incompatible
in-com-pat-i-ble
adjective
Unable to exist or be used together due to fundamental differences.
"Their work schedules were incompatible."
Thesaurus
Synonyms: unsympathetic, uncongenial, disagreeable, contrastive, antonymous, antacid, antiphlogistic, antagonistic, unmixable, immiscible, non-miscible, out of keeping
Antonyms: compatible, congenial, interactive, synergistic