The following word could not be a loanword anymore because it has been modified in an interesting way in Japan.
Nighter (Nai-ta-a)
Races that start at around 3:00 p.m. and end at around 9:00 p.m.
Nighter is one of the most commonly used Japanese-English words, not just in race gambling but also in other fields of events. It usually refers to any type of sporting event, like professional baseball games and soccer games, that is scheduled in the evening. Some Japanese people recognize that the word doesn’t make sense to native English speakers. Still, it has been widely acknowledged in Japan to the extent that anchors of the Japan’s public broadcasting station and journalists in Japan’s traditional newspapers use it in their media.
You can see “nighter” originally came from “night.” So, what about “midnight”? Motorboat, bicycle, and motorcycle racing hold their races until midnight at the latest. Are those races “Midnighter” according to the precedent? The answer is NO. Organizers or fans never say “Midnighter”; they say “Midnight” or “Midnight races” instead.
Suppose you’re frustrated at an inconsistency of conjugation in Japanese or mad at the abusive handling of Western words. In that case, you should watch the video below and scream, “Why Japanese people!” with him. He is a well-known American comedian in Japan.