c. 1200, likur "any matter in a liquid state, a liquid or fluid substance," from Old French licor "fluid, liquid; sap; oil" (12c., Modern French liqueur), from Latin liquorem (nominative liquor) "a liquid, liquor; wine; the sea," originally "liquidity, fluidity," from liquere "be fluid, liquid" (see liquid (adj.)).
Narrowed sense of "fermented or distilled drink" (especially wine) first recorded c. 1300; the broader sense seems to have been obsolete from c. 1700. As long as liquor is in him was a Middle English expression, "as long as he is alive," that is, "as long as he has a drop of blood left." The form in Modern English has been assimilated to Latin, but the old pronunciation persists.
c. 1500, "to moisten," from liquor (n.). From 1550s as "supply with liquor," 1839 as "drink" (intoxicating liquor). To liquor up "get drunk" is from 1845. Related: Liquored; liquoring.