From Longman Dictionary of Contemporary Englishwater something ↔ down phrasal verb1 REDUCEto make a statement, report etc less forceful by changing it or removing parts that may offend people – used to show disapproval The report of the investigation had been watered down. → watered-down2 DFDWATERto add water to a drink to make it less strong SYN dilute → water→ See Verb table
Examples from the Corpus
water down• As the mountains are raised, erosion by wind, ice, and water wears them down.• Straw in Water Place the straw in the glass of water.• Trickles of water ran down inside his collar.• And we had to keep our water supply low down, or the risk of capsize would be unacceptable.• The water came down so fast from the cold heights that it remained icy even in the thick heat of the valley.• It is easy to see why the water table goes down so rapidly.• He listened to the water course down the pipe into the bowl beneath.• Sport-watches Divers will be pleased to hear that Fila have introduced a watch water resistant down to 330 feet.From Longman Business Dictionarywater something → down phrasal verb [transitive] to make a suggestion, rule, or proposal less forceful by removing some parts of itA late amendment watered down the insider-trading penalties to a £100,000 maximum fine instead of the earlier £500,000. —watered-down adjective [only before a noun]Legislators want to offer awatered-down version in hopes that it will satisfy voters. → water→ See Verb table 