1An insulting term for a worthless or good-for-nothing person; a ne'er-do-well.
あいつは約束を守らない、まったくのろくでなしだ。
He doesn't keep promises — a complete good-for-nothing.
母は昔、父の若いころを『ろくでなしだった』と笑って話した。
My mother used to laugh and say my father was a bit of a ne'er-do-well when he was young.
友だち同士の冗談でも『ろくでなし！』と言うときは口調に注意しよう。
Even when joking among friends, be careful with the tone if you call someone a 'good-for-nothing!'