A paying guest
'Paying guest' is an archetype of euphemistic language. It was invented specifically to avoid the embarrassment of acknowledging that one took lodgers into one's house in order to make ends meet. Perhaps it isn't surprising that it originated at a time and place that is known for social awkwardness, Victorian England. There are references in print to paying guest dating from the early 1800s but they relate to payment for hotel rooms etc. The first citation that I can find that refers to a payment for lodgings in a private house is from the UK newspaper The Wells Journal, August 1894:
He was a tutor ostensibly, but he was also a paying guest.