an exclusive word used in Taiwan and Hong Kong. Recently rising in twitch chat on Taiwanese channel.
Which means "idiot".
87 be pronounced "ba - chi" in two separate numbers in Chinese. but its pronunciation is similar to "bei - chi", which means "idiot" in Mandarin Chinese.
The term 87 (Derived from gasoline octane‘s ) is used to describe somebody in a bad way usually associated with being a snake, cheating, a total menace, or just being a shitty person in general.