WordNet records no synonym and no antonym for double blind. It is the only member of its synset, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
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.
a test procedure in which the identity of those receiving the intervention is concealed from both the administrators and the subjects until after the test is completed; designed to reduce or eliminate bias in the results
Synonyms, antonyms and the broader and narrower relations for double blind come from Princeton University’s WordNet. Full sources and licences.