used to say that it does not matter who does something, is in a particular place etc:
I'll take whoever wants to go.
When you're done with the book, just give it to Kristin or Shelley or whoever.
used to talk about a specific person or people, although you do not know who they are:
Whoever is responsible for this will be punished.
3 also whoever he/she may be
used to say that you do not know who someone is:
You've got a message from Tony Gower, whoever he is.
used to mean 'who' at the beginning of a question to show surprise or anger:
Whoever would do a thing like that to an old woman?