case the tenant doing the subletting makes a profit off of the transaction. For example, a single man renting a 5 bedroom house and then subletting 4 of the rooms out to other individuals at a premium so he doesn't end up paying anything for rent.

What you are referring to is technically subletting but in reality most landlords are ok with it as long as there is a vetting process that they do and the actual lease is transferred to the other individual.