Front desk, 11 p.m., phone at 4%.
You: "Excuse me — is there a consent in the room?"
Receptionist: (0.8 seconds of nothing) "…はい？"
You hold up your charger. Everything resolves instantly. Nobody involved will ever discuss it again.
The word is believed to come from "concentric plug", an old term that arrived in Japan with early electrical fittings and then quietly outlived it everywhere else on earth.
In practical terms コンセント is the wall socket, and it is the word you want in a hotel, café, airport or on a shinkansen. Say it while pointing at your charger and your problem is solved in one second.
It also has a wonderful side effect: it makes English-language legal documents about consent quietly hilarious for anyone bilingual, which is a burden Japanese interpreters carry silently every day.
This one is not Japanese English at all. It is fossil English — a genuine term from early 20th-century electrical catalogues, preserved perfectly here after the rest of the English-speaking world dropped it. Japan did not break the word. Japan is the last place still using it, which technically makes everyone else the ones who changed.