Fat black man titties, where a black man (a brother aka bro) has sacks of fat (breasts/man boobs) on his chest. They may grow there from puberty, genetic defects, eating too many potatoes or be placed there by god because he deserved it. May have increased risk to develop breast cancer.
Therefore bro + boobs = broobs
"That frank guy...i heard hes got broobs"
"Yer we should call him broobs from now on"
"Broobs if you keep eating potatoes its not gonna help the broobs situation"
"F*ck off broobs"
"frank youve got some serious broobs"
"Can i touch your broobs frank?"