Here's what rhymes with onomatopoeic.

Consider these alternatives

euphemistic / characteristic overused / used untranslatable / double neologism / biologism anagram / can antonym / him pronunciations / relations mnemonic / chronic derivation / education cognate / donate archaism / given grammatically / mathematically ekphrasis / basis epigraph / half allusive / inclusive transliterations / relations exclamatory / story metaphoric / historic