Unreasonable or irrational; unfair, absurd, or not making sense; something that defies reason or fairness.
上司の理不尽な要求に部下は困り果てている。
Employees are at a loss because of their boss's unreasonable demands.
そんな理不尽な理由で解雇されるはずがない。
There's no way someone would be fired for such an unreasonable reason.
人生には理不尽なことが時々起こる。
Unreasonable things sometimes happen in life.