A spirit is a distilled beverage or liquor; a drinkable liquid containing ethanol that is produced by distilling fermented grain, fruit, or vegetables. This excludes undistilled fermented beverages such as beer, wine, and hard cider.
The term hard liquor is often used in the United States to distinguish distilled beverages from undistilled ones (implicitly weaker).
Almost all cocktails contain spirits of some kind. The few that do not are usually called "virgin" versions of the standard cocktails.