A Brononym is a synonym for the word
bro, used when someone has been called
bro and needs to respond with another
bro-like word.
At the end of the 2009 film, "I Love You, Man", both Peter Klaven (Paul Rudd) and Sydney Fife (Jason Segel) engage in a Broathlon inlcuding the brononyms: Man, Bro Montana, Bud, Dude, Brosiph Goebbels etc...
Bro1: Sup
bro
Bro2: Not a whole lot brodike
Bro1: Woah dude, no need to be a brodouche
Bro2: Suck it Han
brolo
Bro1: You suck it broklahoma
Bro2: Whatever, brohio
Bro1: Hahaha, those were some good brononyms bro back
mountain