(adv/adj) Denoting work undertaken by a bro for the good of one's bro without compensation, esp. when that bro needs help moving, a ride to the airport, or even a temporary wingman. Such work is considered just as noble, or perhaps nobler, than other voluntary service.
(adv) I do kinda have something else broing on
tonight, but after I rackjack
ed Ted last night, I feel like I have to throw him a brone
and help him hook up with Robin pro brono.
(adj) Might I enlist your pro brono services, gentlemen? This Tijuana prostitute isn't going to bury itself!