Liquor is a synonym for alcohol, usually a fermented drink that has been distilled. Distillation is basically the process of taking a fermented liquid and purifying it which removes water and therefore makes the concentration of alcohol higher. In North America, hard liquor is a common synonym.
As a verb, to liquor something is to either coat it with oil or grease, or it can mean to drink enough alcohol to become drunk. The latter definition is usually used with the preposition up.
Liqueur is a liquor that is mixed with herbs and spices, usually to make the flavor sweeter.
There are caveats to these definitions. For example, there is a chocolate liquor and a chocolate liqueur. The liquor is a distillation of fermented cocoa beans. The liqueur is a alcoholic beverage which tastes like chocolate.
Examples
The friends were returning after enjoying liquor at a New Year bash when robbers decamped with valuables worth 40,000 from the duo. [Times of India]
Microbrewing has become a hopping business in Saskatchewan in the last few years, and local brewers say liquor laws need to be revised to keep it that way. [CBC]
Almost everyone agrees that brown liquors are the way to go, but beyond that, the consensus breaks down. [Huffington Post]
But once Deb and Chip are safely liquored up in their Caribbean beach hideaway, we are introduced to a thinly drawn hoard of supporting characters who, when they’re anything more than just names, are simple cardboard types. [Toronto Star]
Liquoring up a preview audience is a pretty good sign that a studio had less than complete faith in a film, though in this case maybe the drinks were just to calm our nerves. [The New York Times]
The festive liqueur, doled out in comically small glasses to a roomful of torpid relatives, is, like the party hat, the Brussels sprout and the soap-opera dust-up, a seasonal tradition in need of a reboot. [The Telegraph]
In the traditional liqueurs category, the judges were impressed by Giffard’s Menthe-Pastille, a mint liqueur that, with a nose of crushed Polos and a palate of After Eight centres, scored the only Master of the round. [Daily Mail]