liquidyoudaoicibaDictYouDict[liquid 词源字典]
liquid: [14] Latin liquēre meant ‘be fluid’. From it was derived the adjective liquidus, which reached English via Old French (it was not used as a noun in the sense ‘liquid substance’ until the early 18th century). Also derived from liquēre was the noun liquor, which passed into Old French as licur or licour. English has borrowed this twice: first in the 13th century as licour, which was subsequently ‘re-latinized’ as liquor, and then in the 18th century in the form of its modern French descendant liqueur.

From the same ultimate source come liquefy [16], liquidate [16] (which goes back to a metaphorical sense of Latin liquēre, ‘be clear’ – thus ‘clear a debt’; the modern meaning ‘destroy’ was directly inspired by Russian likvidirovat’), and the final syllable of prolix[15].
=> liquor, prolix[liquid etymology, liquid origin, 英语词源]
liquid (adj.)youdaoicibaDictYouDict
late 14c., from Old French liquide "liquid, running," from Latin liquidus "fluid, liquid, moist," figuratively "flowing, continuing," from liquere "be fluid," related to liqui "to melt, flow," from PIE *wleik- "to flow, run." Of sounds, from 1630s (the Latin word also was used of sounds). Financial sense of "capable of being converted to cash" is first recorded 1818.
liquid (n.)youdaoicibaDictYouDict
"a liquid substance," 1709, from liquid (adj.). Earlier it meant "sound of a liquid consonant" (1520s).