A derivative of the word "robusto", a size of cigar, the word can function as both an adjective and a noun. In adjectival form, brobusto is used to describe a particular robust activity taken up with bros. Or just a greatly positive adjective. In noun form, replace your bro's name with brobusto. Also, the antonym is "nobusto".
Dude, I thought that girl was brobusto, but her face was nobusto.