Translation of quienquiera

Some idiot copied it from there and inserted it into our vocabulary builder. He is allowed to do it as long as he indicates that sentences where taken from another source and are for self usage only.
It certainly is one of the reasons that a student from abroad is not as good in English as people who were born in America. This is an obstacle for all students and a challenge for the educational system.
Why did you sit on the box? You obviously did not know that there were presents inside. Now, seriously, do you have a backup plan? We must buy new gifts if we want to go to the party.?