1] (noun) a person with little knowledge of a subject that another person greatly understands; 2] (adj.) undereducated, retarded, not knowledgeable in a subject; 3] (adj.) hard to understand, confusing, undecipherable (as used by John Cleese in Monty Python's Flying Circus, Ep. 5, "The Smuggler")
1] You don't understand quantum physics? My god, you're such a glib.
2] Matt, Matt, Matt, you don't even — you're glib. You don't even know what Ritalin is.
3] That come out a bit glib, didn't it?