Noun, portmanteau of "men" and "engaged."
A term to describe two guys (generally at least one het) who are in a very serious bromance. The two generally go on to rent an apartment and lead a bromarried lifestyle full of video games, watching Indiana Jones and, ideally, jerking each other off.
"Who's that TJ guy who's always with Sam lately? I thought he was straight."
"Yeah, they're straight, but practically mengaged."