불행하다 means “to be unhappy” or “to be unfortunate”. It describes a state of dissatisfaction, misfortune, or suffering.
Here are some example sentences using 불행하다:
그 소식을 듣고 매우 불행했어요. I was very unhappy when I heard that news.
그녀는 많은 돈을 가졌지만 여전히 불행하다. She has a lot of money, but she is still unhappy.
그는 자신의 삶이 불행하다고 느낀다. He feels that his life is unfortunate.
The opposite of 불행하다 is 행복하다, which means “to be happy.”