Definition of "a whole nother"
a whole nother
determiner
(US, informal) An intensified form of another: an entirely different; a whole other.
Quotations
"Will the fog be gone by to-morrow morning?" said Patty, disconsolately. "I don't know what we shall do if we have to be a whole 'nother day in the house and in the dark."
1887 October 29, [Mary Louisa] Molesworth, “The Mysterious Guide: A Story of a London Fog”, in [Charles Peters], editor, The Girl’s Own Paper, volume IX, number 409, London: “The Leisure Hour” Office, page 67, column 3
The problem is when you physically try to impede my progress—then it moves up to a whole 'nother level that you probably can't handle me on. If it's just words, mean little things, I'm not [Joseph] Stalin, say what you want. Get in my way, it's a whole 'nother thing.
2004, Michael W. Dean, quoting Henry Rollins, “Interviews”, in $30 Music School, Boston, Mass.: Muska & Lipman, Course Technology, page 457
Executing it all well, with the feel, look and operation of a real luxury car, is a whole nother ball of wax.
2009 October 1, Don Chaikin, “Long-Term Test Cars: Azera, Sedon M35, Highlander Hybrid, Liberty Sport CRD, Cobalt SS”, in Jim Meigs, editor, Popular Mechanics, New York, N.Y.: The Hearst Corporation, archived from the original on 2013-10-01