a homosexual male who disguises his sexulaity in order to get ahead
-"Look at our old mate behind the bar with his bumchum. This was a great pub, no look at it - cocktails, no real ale - and full of style-conscious genlemen with nice fingernails"
-"yeah, our old mate was always a stealth bummer. He'd come and join us with his frustrated wife and join us, but he was just casing the joint."
-"yeah, taken out by a stealth bummer!"
A man who has successfully concealed his sexuality to take advantage of his heterosexual friends.
Bert - "The pub went queer under the new owner, our lawyer friend. No more real beer, no more blazing fire. Now it's strictly for "style conscious gentlemen" only.
Bill - "Yeah we're done for now - nowhere left to go in the village. Sad. And we thought Mike was one of us. He was just casing the joint. Look at it now - all mirrors and pictures of fucking male pop stars and stuff and shitty music."
Bert - "Makes you sick. Our last real watering hole taken out by a stealth bummer!"
Someone who is obviously gay but hides it from the world for some reasons which are usually not so plain to see.
Greig's not gay (even though he's fucked everyone this side of manchester)