From Longman Dictionary of Contemporary Englishpolysyllabicpol‧y‧syl‧lab‧ic /ˌpɒlisɪˈlæbɪk◂ $ ˌpɑː-/ adjective technicalSL a polysyllabic word has three or more syllables → monosyllabic —polysyllable /ˈpɒliˌsɪləbəl $ ˈpɑː-/ noun [countable]
Examples from the Corpus
polysyllabic• She resists the polysyllabic playfulness that marks the writing of her brother, Bill, but she writes with clarity and style. 