I've suggested for years that employer implies to a houseboy that he will be paid for services, (even if it may be in trade for room, room & board, etc). In an effort to ensure that this doesn't turn into an escort site I've asked for the title to be reconsidered again, but the suggestion back is that I should post it in the forums to be discussed. When doing an internet search for "Antonyms for house boy", two titles come up: boss and master. I've placed a few examples in a poll to see what others think as well!
