From Longman Dictionary of Contemporary Englishwatered-downˌwatered-ˈdown adjective REDUCEa watered-down plan, report etc has been changed so that it is less extreme or forceful than when it was first written – used to show disapproval → water down a watered-down version of the original
Examples from the Corpus
watered-down• Courses should not be watered-down linguistics.• It has to be understood that the general and critical does not mean the vague, the watered-down, or the journalistic.• He is the only major figure offering an alternative party programme which is not a watered-down version of Mrs Thatcher's.• The House approved a watered-down version of the bill in November.watered-down version• He is the only major figure offering an alternative party programme which is not a watered-down version of Mrs Thatcher's. 