two actions, ideas, etc. that are incompatible are not acceptable or possible together because of basic differences

two people who are incompatible are very different from each other and so are not able to live or work happily together

She and her husband soon proved to be totally incompatible.

two things that are incompatible are of different types so that they cannot be used or mixed together

New computer software is often incompatible with older computers.

Those two blood groups are incompatible.

LEARNit Dictionary