liquidate has 6 distinct synonyms spread across 2 of its 4 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
get rid of (someone who may be a threat) by killing
“The mafia liquidated the informer”
eliminate by paying off (debts)
Synonyms, antonyms and the broader and narrower relations for liquidate come from Princeton University’s WordNet. Full sources and licences.
convert into cash
“I had to liquidate my holdings to pay off my ex-husband”
settle the affairs of by determining the debts and applying the assets to pay them off
“liquidate a company”