- youˈ-know-whatˈ, youˈ-know-whoˈ nounSome unspecified but well-understood or well-known thing or person• • •Main Entry: ↑you
* * *noun [noncount]informal1— used in speech to refer to something that is not named but is known to both the hearer and speaker
I've hidden the you-know-what in the closet.2— used in place of a rude or offensive word in order to express anger or annoyance
He's a complete you-know-what.
That's a big pile of you-know-what.
Useful english dictionary. 2012.