Or search: unreal, unbodied, extraneous, intangible, irrelevant, orthogonal, unembodied, disembodied, impertinent, indifferent, materiality, unimportant, corporality, incorporeal, nonmaterial
2 Syllables: SU
cereal, cheerful, Cyril, fearful, filial, Israel, Israel's, lineal, medial, menial, serial, tearful, trivial, venial, virile, vitriol
3 Syllables: USU
arterial, bacterial, convivial, ethereal, funereal, imperial, material, remedial, venereal
4 Syllables: UUSU
magisterial, managerial, ministerial, uncongenial

Found 29 words across 3 groupings. Skipped 2 excess words of a similar stem.