As nouns the difference between bitters and liqueur

is that bitters is a liquid used in mixed drinks or as a tonic into which bitter herbs have been steeped (it can also be found in powdered form for adding to mixed drinks) while liqueur is a flavored alcoholic beverage that is usually very sweet and contains a high percentage of alcohol cordials are a type of liqueur manufactured using the infusion process as opposed to the essence and distillation processes.