Or search: pit, oppose, tackle, encounter
1 Syllable: S
2 Syllables: SU
2 Syllables: US
affront, Amiens, among, amongst, become, begun, benumbed, Bodleian, confronts, Crimean, defunct, expunged, Korean, Lyceum, outdone, outrun, plebeian, succumb, therefrom, undone
3 Syllables: SUU
3 Syllables: UUS
4 Syllables: UUUS

Found 160 words across 6 groupings. Skipped 49 excess words of a similar stem.