Sloth is the sin of doing nothing at all, and is one of the Seven Deadly Sins. Sloth can take the form of general laziness and reluctance to exert oneself, or a failure to do specific things that one ought to do. For example, a man who stands idly by while a crime is committed instead of stepping in to prevent it is guilty of sloth, even if he is not directly involved in the crime itself.
One of the most famous examples of sloth is Pontius Pilate's 'washing his hands' of Jesus' case and allowing Him to be put to death, when it was in his power to free Him. More generally, inactive rulers may be considered slothful: Dante's Purgatorio has a whole section devoted to rulers such as Henry III who did little wrong, but did not use their power to advance the cause of good.