incorrigible

尽管多次被警告，他仍然是个无可救药的骗子。

Despite many warnings, he remains an ___incorrigible liar.

即便在崩盘后失去了一切，他仍然是个无可救药的乐天派。

Even after losing everything in the crash, he remained an ___incorrigible optimist.

我奶奶是个积习难改的旧茶杯收藏者，柜子早就塞不下了。

My grandmother is an ___incorrigible collector of old teacups, and the cabinets are overflowing.