WordNet (r) 3.0 (2006):

spinsterhood
    n 1: the state of being a spinster (usually an elderly unmarried
         woman)

Moby Thesaurus II by Grady Ward, 1.0:

18 Moby Thesaurus words for "spinsterhood":
   bachelordom, bachelorhood, bachelorism, bachelorship, celibacy,
   continence, maidenhead, maidenhood, misogamy, misogyny, monachism,
   monasticism, single blessedness, single state, singleness,
   unwed state, virgin state, virginity