Green’s Dictionary of Slang

cheez whiz n.

also cheese whiz
[cheese n.1 (3a) + pun on the name of a proprietary US cheese spread]

(US campus) someone who mistakenly thinks that they are impressive; something considered socially unacceptable.

[US]P. Munro Sl. U. 57: cheez whiz 1. out-of-date, cheesy. 2. something that’s out-of-date or cheesy.
[US]Eble Sl. and Sociability 70: Cheese became a metaphor for ‘something unattractive or undesirable’ and gave rise to cheeseball, cheezy, velveeta, cheese whiz.