From Longman Dictionary of Contemporary Englishgee whizˌgee ˈwhiz interjection American English old-fashioned SURPRISEDused to show that you are surprised or annoyed
Examples from the Corpus
gee whiz• But gee whiz, there are other schools in town equally deserving of coverage.gee-whizgee-ˈwhiz adjective American English informal very good, in a way that is impressive and exciting gee-whiz graphicsExamples from the Corpus
gee-whiz• the gee-whiz graphics of a computer game 