Oneill rhymes with:
o'neal, o'neil, o'neill, oneal, oneil, anneal, corneal, corniel, daneel, kneale, kneel, macneal, macneil, macneill, mcneal, mcneel, mcneil, mcneill, mcniel, menil, neal, neale, neall, neel, neil, neile, neill, niel, o'neal, o'neil, o'neill, oneal, oneil
Oneill sounds like:
o'malley, o'neal, o'neil, o'neill, omalley, omelia, oneal, oneall, oneil, onley, only