WordNet records no synonym and no antonym for silenus. It is the only member of each of its synsets, 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.
any of the minor woodland deities who were companions of Dionysus (similar to the satyrs)
the chief satyr in the service of Bacchus; father of Dionysus; usually depicted as drunk and jolly and riding a donkey
Synonyms, antonyms and the broader and narrower relations for silenus come from Princeton University’s WordNet. Full sources and licences.