The adjective gauche means “lacking social grace”, “awkward”, or “crude”. It comes from the French word gauche, meaning “left”, which came from a similar but older French word that meant “to trample” or “walk clumsily” (see the OED for more).
Now why would the word for “awkward” be so closely related to the word for “left”? And why does the word “right” also mean “correct”? Clearly, one direction is considered better than the other. Check out Wikipedia’s blurb on the social stigma of left-handedness for some more language trivia that at least partially explains the bias.