668
Singular they rule
(pawb.social)
Be sure to follow the rule before you head out.
Rule: You must post before you leave.
Care to give examples?
No, examples of words that mean two opposite things at the same time, since you apparently said that every single word in existence has always been that way. "Bad" comes to mind, though it's a lot easier to tell from context which meaning it has compared to "literally."
Another non-english example would be the german word "umfahren" which can mean both driving around or over something, depending on context