Lack of filial piety; behaving in a way that is unfilial or disobedient to one's parents.
息子が実家にほとんど帰らないので、母は親不孝だと嘆いている。
Because her son hardly returns home, his mother laments that he is unfilial.
親不孝者（おやふこうもの）という言い方は古風だが、意味は理解される。
"Oyafukoumono" (an unfilial person) is an old-fashioned expression, but its meaning is understood.
親不孝と言われないように、手紙を書いて近況を報告した。
So as not to be called unfilial, I wrote a letter to report my recent situation.