Source : Webster's Revised Unabridged Dictionary (1913)

Glib \Glib\, v. t. [Cf. O. & Prov. E. lib to castrate, geld,
   Prov. Dan. live, LG. & OD. lubben.]
   To castrate; to geld; to emasculate. [Obs.] --Shak.

Glib \Glib\, a. [Compar. {Glibber}; superl. {Glibbest}.] [Prob.
   fr. D. glibberen, glippen, to slide, glibberig, glipperig,
   glib, slippery.]
   1. Smooth; slippery; as, ice is glib. [Obs.]

   2. Speaking or spoken smoothly and with flippant rapidity;
      fluent; voluble; as, a glib tongue; a glib speech.

            I want that glib and oily art, To speak and purpose
            not.                                  --Shak.

   Syn: Slippery; smooth; fluent; voluble; flippant.

Glib \Glib\, v. t.
   To make glib. [Obs.] --Bp. Hall.

Glib \Glib\, n. [Ir. & Gael. glib a lock of hair.]
   A thick lock of hair, hanging over the eyes. [Obs.]

         The Irish have, from the Scythians, mantles and long
         glibs, which is a thick curied bush of hair hanging
         down over their eyes, and monstrously disguising them.
                                                  --Spenser.

         Their wild costume of the glib and mantle. --Southey.

Source : WordNet®

glib
     adj 1: marked by lack of intellectual depth; "glib
            generalizations"; "a glib response to a complex
            question"
     2: having only superficial plausibility; "glib promises"; "a
        slick commercial" [syn: {pat}, {slick}]
     3: artfully persuasive in speech; "a glib tongue"; "a
        smooth-tongued hypocrite" [syn: {glib-tongued}, {smooth-tongued}]
     [also: {glibbest}, {glibber}]