The Collaborative International Dictionary of English v.0.48:

flophouse \flophouse\ n.
   a cheap and usually seedy lodging house or hotel.

   Syn: dosshouse.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

flophouse
    n 1: a cheap lodging house [syn: flophouse, dosshouse]

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "flophouse":
   boardinghouse, dorm, dormitory, doss house, fleabag, guest house,
   hospice, hostel, hostelry, hotel, inn, lodging house, ordinary,
   pension, posada, pub, public, public house, roadhouse,
   rooming house, tavern