JR here is not junior, and it is not a train line. It is J.R. Ewing, a man from the American television show Dallas, which Taiwan showed as 《朱門恩怨》 in the late 1970s and 1980s. He ran the family's oil business in Texas. He was good at making money and bad at being honest. He smiled, he plotted, and he seemed to want money and power more than anything else. For years almost everyone knew him; “Who shot J.R.?” was a huge question around the world. If an older English text says someone is “a real JR,” they mean a smooth, greedy businessman like that character, not a boy named Junior.

《朱門恩怨》（Dallas）裡的石油商人 J.R. Ewing