whoever
Concise Oxford English Dictionary © 2008 Oxford University Press:
whoever/huːˈevə(r)/
▶relative pronoun the person or people who; any person who.
■ regardless of who.
▶interrogative pronoun used for emphasis instead of ‘who’ in questions.usage: In the emphatic use (whoever does he think he is?) either whoever or who ever is acceptable. See usage at however.
'whoever' also found in these Oxford entries:
