noun
A lodging house that accepts guests without special requirements; often implies a simple, unpretentious place.
学生時代は素人下宿に住んでいた。
When I was a student, I lived in a boarding house.
Compound of 素人 (しろうと, 'amateur, ordinary person') and 下宿 (げしゅく, 'lodging'). The exact historical derivation is uncertain; the term likely refers to a boarding house that accepts anyone without special credentials.