"Outside Residence"

http://www.bmezine.com/tattoo/A30419/high/pictures2153.jpg

The character 外 means "out, outside, external; foreign", and the character 宅 means "residence, dwelling, home".

If the tattooed phrase was read from right-to-left, it would mean "the exterior of a house".

But if it was read from left-to-right, then it would mean "outside house" or "out house":

outhouse n : a small outbuilding with a bench having holes through which a user can defecate.