n. a man who services married/committed women i.e. the other guy. The original meaning derives from blues lingo and refers to the guy who comes in through the backdoor of the house, it has nothing to do with anal sex.

A cultural and aesthetic mind-state that prioritizes making money, even as an “underground” or “radical” creator. The work isn’t made for money, but it’s the money that matters the most.

A married woman's lover, who is, incidentally, a legendary figure in blues numbers.

the man that some ones wife is seein on the side. usualy came to the back door to avoid any other house wives seein him.

Fucking a married woman.

The naked man that is running out your back door when your walking in from a hard days work to support your unfaithful wife.

more background:
because the man she's cheating with would often use her "back door" for sex, have sex anally, so that the husband wouldn't detect she's had sex with someone else (if he had sex with her later). Also, for the woman, to avoid pregnancy by someone other than her husband. (and thus, avoid getting caught cheating when the baby didn't look like, or was a different color than, the husband.