words ending in onian

4 Syllables
devonian, draconian, estonian, etonian, newtonian, oxonian, plutonian, slavonian

Now you can make multisyllabic rhymes in the new rhymit app :)

Get rhymit app screenshot
Get rhymit on Google playDownload in app store
5 Syllables
caledonian, ciceronian, macedonian
6 Syllables
lacedaemonian