Neat drinks are about two ounces, not chilled, there are no extra ingredients (even ice) and no, you can't order an Irish Car Bomb neat. Brandy and whiskey are the most popular spirits to drink neat. High-quality spirits of any kind are commonly enjoyed neat as well.
Neat is used to order a drink that is served with no ice or mixers. It is, quite simply, a straight pour of liquor from the bottle into the glass. Neat drinks also are served at room temperature.