Unjust, improper, or unwarranted; not reasonable or deserved in terms of rights or fairness.
会社の解雇が不当だとして労働組合が抗議した。
The labor union protested, claiming the company's dismissal was unjust.
不当な差別は法律で禁止されている。
Unjust discrimination is prohibited by law.
その処分は重すぎて不当だと思う。
I think that punishment is too severe and unjust.