2 Syllables: SU
bidden, bidding, billing, bridging, brimming, bristling, building, cheering, chilling, chipping, christening, clearing, clicking, clipping, crippling, differing, digging, dipping, drilling, dripping, earrings, fearing, filling, fishing, fitting, flitting, gearing, getting, Gibbons, giggling, gilding, given, giving, glistening, Griffin, grinning, gripping, Higgins, hissing, hitting, itching, kicking, killing, Kipling, kissing, knitting, licking, listening, listing, living, middling, Mifflin, milking, milling, missing, nearing, nibbling, picking, pigeon, pilgrim, pinning, pitching, pitting, pricking, printing, quitting, rearing, ridding, rigging, ripping, rippling, risking, scribbling, shearing, shilling, shipping, siblings, sinning, sipping, sitting, skimming, skipping, slipping, smiting, sneering, sniffing, spilling, spinning, spitting, splitting, steering, sticking, stitching, stripling, stripping, swimming, switching, syringe, tearing, thinning, thrilling, ticking, tilings, tilling, tilting, tipping, trickling, trimming, tripping, twisting, twitching, whipping, whistling, Wilkins, willing, winning, wishing, writhing
3 Syllables: USU
adhering, admitting, appearing, assisting, befitting, beginning, bewitching, committing, consisting, dismissing, distilling, emitting, enlisting, enriching, equipping, existing, forbidding, forgiving, fulfilling, insisting, misgiving, omitting, permitting, persisting, reappearing, rebuilding, remitting, resisting, submitting, subsisting, thanksgiving, transmitting, unwilling, unwitting
4 Syllables: UUSU
disappearing, domineering, engineering, interfering, persevering, pioneering, preexisting, unremitting, volunteering
5 Syllables: UUUSU
Found 162 words across 4 groupings. Skipped 11 excess words of a similar stem.