turpitude n.

"depravity, infamy, inherent baseness or vileness," late 15c., from Old French turpitude (early 15c.), from Latin turpitudinem (nominative turpitudo) "baseness," from turpis "vile, foul, physically ugly, base, unsightly," figuratively "morally ugly, scandalous, shameful," a word of uncertain origin. De Vaan finds proposed connections to IE words meaning "to turn" (via the notion of "to turn away") as "too constructed" to be credible. Klein suggests perhaps originally "what one turns away from" (compare Latin trepit "he turns").