The Collaborative International Dictionary of English v.0.48:

Frounce \Frounce\, v. i. [imp. & p. p. Frounced; p. pr. & vb.
   n. Frouncing.] [OE. frouncen, fronsen, to told, wrinkle,
   OF. froncier, F. froncer, perh. fr. an assumed LL. frontiare
   to wrinkle the forehead, L. frons forehead. See Front, and
   cf. Flounce part of a dress.]
   To gather into or adorn with plaits, as a dress; to form
   wrinkles in or upon; to curl or frizzle, as the hair.
   [1913 Webster]

         Not tricked and frounced, as she was wont. --Milton.
   [1913 Webster]