Unfortunate is a euphemism for prostitute.
Interestingly, the term 'prostitute' does not appear in the occupational dictionaries used to abstract data in the Census Office. However the feelings of enumerators do show. In the 1871 Census one enumerator described every prostitute as 'fallen' in the occupational column. Another euphemism for prostitute, 'unfortunate', seems to have been struck out of the census returns, see the 1901 census RG13/322 folio 37, page 19. Limehouse, London."
from 'Making Sense of the Census' Edward Higgs.
Stan