Glib
glib, adj. fluent and voluble but insincere and shallow from glibberig, slimy
Glib lives at an intersection with four corners leased by skyscraper terms. Fluent, voluble, insincere, and shallow.
Please, allow me:
- Fluent: Flowing or capable of flowing; liquid; glodding.
- Voluble: Easily rolling or turning; easily set in motion; apt to roll.
- Insincere: Not being in truth what one appears to be.
- Shallow: Not deep; having little depth; shoal.
Glib is all that. Glib is ready-to-flow, it’s “glodding,” it’s not the whole truth, nothing but the truth, it’s barely a scratch. Glib is four volumes in four letters and we’re just getting started.
It describes words, or a person speaking those (glib) words, or the manner in which a (glib) person speaks those (glib) words, viz., glibly. What about all three at once? Not a problem.
(This is known as glib cubed.)
Its original meaning, not used much any more, is “slippery.” 
Glib is like an an electric eel. Glib is a reused speech. Glib is not the answer you were expecting.
Glib is a baseball bat sheathed with a wool sock. And it’s not one you want the business end of, especially in the dark. Any math that pretends to contain the domain and range of glib is bound to make you lose your grip.