Source : Webster's Revised Unabridged Dictionary (1913)

Light-o'-love \Light"-o'-love`\ (l[imac]t"[-o]-l[u^]v`), n.
   1. An old tune of a dance, the name of which made it a
      proverbial expression of levity, especially in love
      matters. --Nares. ``Best sing it to the tune of
      light-o'-love.'' --Shak.

   2. Hence: A light or wanton woman. --Beau. & Fl.

Source : WordNet®

light-o'-love
     n : a woman inconstant in love [syn: {light-of-love}]