To inure is to get used to something difficult or unpleasant. If after spending an hour in your brother's room, you stop noticing the stinky-sock smell, you have become inured to the odor.
Although the Latin roots of inure mean "in work," it may be easier to think of "in use" when you see inure. Got new shoes that give you blisters? When they are "in use" long enough, your feet will become inured to the spots that rub, and while you may have calluses, you will not be in pain. You can be inured to more abstract things too. When weathermen constantly play up the next big snowstorm or blizzard, you become inured to it and stop paying attention to them.