whoever
1 conj You use whoever to refer to someone when their identity is not yet known.
Whoever wins the election is going to have a tough job getting the economy back on its feet...
2 conj You use whoever to indicate that the actual identity of the person who does something will not affect a situation.
You can have whoever you like to visit you...
3 quest You use whoever in questions as an emphatic way of saying `who', usually when you are surprised about something., (emphasis)
(=who)
Ridiculous! Whoever suggested such a thing?