caitiff

From the Dictionary.com feed in the right-hand column

caitiff \KAY-tif\, noun, adjective:
1. cowardly and mean

noun:
1. a mean, cowardly person

Dictionary.com is a great website; I love their feed and when I need to look up the meaning of a word it's where I always go.

I also like how they give examples of a word, such as a snippet out of an article or book. Here's one they used for caitiff:

But there was no need: the towering threat and the flaming eye and the swift rush buffeted the caitiff away: he recoiled three steps, and nearly fell down.
-- Charles Reade, The Atlantic, 6/1/1943

caitliff = "cowardly and mean".

I really didn't need the example; I've "met" a million caitiffs in forums and message boards.