shameless; shameless person
Used as a noun or adjectival noun to describe someone who lacks shame or acts without embarrassment. Often carries a strong negative judgment.
He is a shameless person who doesn't care even when he lies.
あんな恥知らずな行動は許せない。
I can't forgive such shameless behavior.
He's a shameless person who doesn't care even when he breaks his promises.
Stealing someone's things and acting like nothing happened—he's shameless.
He shamelessly never paid back the money he borrowed.