>You said it: as a noun. IOW, there's no such noun in English.
>
>Sure there is.

Haven't seen it in your message. Did it vanish together with the other medical slang reference? (I saw it - cute!)

>That's not the same. Invalid is a disabled person - check in other languages.
>
>"Ill" eventually includes impairement/disablement in its definition, too. ;-)

Eventually, maybe, but not from the outset. You don't get the status of an invalid for a flu, but you are ill, ergo bolesnik.