An italian expression mixing "caga" or "caca" that means pooping, and "sburra" or "sborra" that means cum(or "cuming".
It is used as a nonsensical expression to let people almost get the meaning of it, but then no, it is a wtf word that will shock your italian friend for the beautifulness of the juxtaposition of those two words.
"Va bene Ciro, dormi pure."
Ciro: "Ho fatto, ho fatto la cagasburra"
A person who is generally stupid in deducing for a conclusion or a solution to a problem thereby returning to the same problem over and over again.
cacabrains can be smart too if it slides down the hill for ten years because then you can use it in your garden as fertilizer and eat your own caca for thought.