The Collaborative International Dictionary of English v.0.48:

Giglot \Gig"lot\, Giglet \Gig"let\, n. [Cf. Icel. gikkr a pert,
   rude person, Dan. giek a fool, silly man, AS. gagol, g[ae]gl,
   lascivious, wanton, MHG. gogel wanton, giege fool, and E. gig
   a wanton person.]
   A wanton; a lascivious or light, giddy girl. [Obs.]
   [1913 Webster]

         The giglet is willful, and is running upon her fate.
                                                  --Sir W.
                                                  Scott.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Giglot \Gig"lot\, a.
   Giddi; light; inconstant; wanton. [Obs.] "O giglot fortune!"
   --Shak.