"Tish-tosh-mish-mosh" is a whimsical amalgamation of words lacking a precise definition. It is typically employed informally to underscore the notion of an assorted collection of haphazard or unrelated elements. It's akin to using colloquial terms like "crap" or "stuff," signifying a hodgepodge of ideas or things.
"Amidst the tish-tosh-mish-mosh of random items in the attic, I stumbled upon an old treasure chest filled with vintage photographs and forgotten mementos."