ugliness has 3 distinct synonyms spread across 1 of its 2 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. Its one recorded opposite is beauty.
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.
qualities of appearance that do not give pleasure to the senses
Synonyms, antonyms and the broader and narrower relations for ugliness come from Princeton University’s WordNet. Full sources and licences.
the quality of being wicked