Merriam-Webster's Word of the Day for August 05, 2012 is:
wiseacre \WYZE-ay-ker\ noun
: one who pretends to knowledge or cleverness; especially : smart aleck
A few wiseacres in the audience began heckling the young comedian after his first couple of jokes fell flat.
"Following the stuttering relationship between Billy Crystal's smart wiseacre and Meg Ryan's prim moralist, the film undoubtedly owed something to Woody Allen's Annie Hall." From an article in The Irish Times, June 28, 2012
Did you know?
Given the spelling and definition of "wiseacre," you might guess that the word derives from the sense of "wise" meaning "insolent" or "fresh"the sense that gives us "wisecrack" and "wisenheimer." But, in fact, "wiseacre" came to English by a different route; it derived from the Middle Dutch "wijssegger" (meaning "soothsayer"), a modification of the Old High German "wīzzago." "Wiseacre" first appeared in English way back in the late 16th century, while the "insolent" sense of "wise" and the words formed from it are products of the 19th and 20th centuries. The etymologies of "wiseacre" and "wise" are not completely distinct, however; the ancestors of "wiseacre" are loosely tied to the same Old English root that gave us "wise."