2 Syllables: SU
airing, Baring, bearing, bedding, begging, betting, bidden, bidding, billing, blessing, bridging, brimming, bristling, caring, Charing, checking, cheering, chilling, chipping, christening, clearing, clicking, clipping, crippling, daring, deadening, denning, destined, differing, digging, dipping, dreading, dredging, dressing, drilling, dripping, dwelling, earrings, ebbing, edging, Edwin, erring, etching, fearing, felling, fetching, figment, filling, fishing, fitting, fixing, flaring, Fleming, flitting, fretting, gearing, Gibbons, giggling, given, giving, glaring, glistening, Griffin, grinning, gripping, guessing, heading, Helen's, herring, Higgins, hissing, hitting, itching, Jennings, jesting, kicking, killing, Kipling, kissing, knitting, larynx, Lenin, Lessing, letting, leveling, Levin, licking, listening, listing, living, meddling, middling, Mifflin, milling, missing, mixing, nearing, nesting, nestling, netting, nibbling, pairing, paring, pecking, pharynx, picking, pigeon, pinning, pitching, pitting, pledging, pressing, pricking, printing, quitting, reading, rearing, reckoning, resin, resting, ridding, rigging, ripping, rippling, risking, scribbling, selling, setting, settling, sharing, shearing, shedding, shelling, shilling, shipping, siblings, sickening, sinning, sipping, sitting, sketching, skimming, skipping, slipping, smelling, smiting, sneering, sniffing, sparing, spelling, spilling, spinning, spitting, splitting, spreading, squaring, staring, steering, stemming, stepping, sticking, stitching, stressing, stretching, stripling, stripping, swearing, sweating, swelling, swimming, switching, syringe, tearing, telling, testing, thickening, thinning, threading, threatening, threshing, thrilling, ticking, tilings, tilling, tipping, treading, trickling, trimming, tripping, twisting, twitching, vesting, vexing, victim, wearing, wedding, welling, wetting, whipping, whistling, willing, winning, wishing, wrecking, wresting, wrestling, writhing, yelling
3 Syllables: SUU
3 Syllables: USU
abetting, accepting, addressing, adhering, admitting, affecting, affixing, afflicting, alleging, annexing, appearing, arresting, assessing, assisting, attesting, befitting, begetting, beginning, besetting, bewitching, caressing, clandestine, collecting, committing, comparing, compelling, compressing, condemning, confessing, conflicting, connecting, consenting, consisting, contesting, correcting, declaring, depicting, depressing, descendants, despairing, detecting, directing, direction, dismissing, dispelling, dissecting, dissenting, distilling, distressing, electing, emitting, endeavoring, enlisting, enriching, equipping, erecting, excelling, excepting, existing, expecting, expelling, expressing, forbearing, forbidding, foretelling, forgetting, forgiving, fulfilling, impairing, impelling, impressing, indwelling, infecting, inflicting, injecting, insisting, inspecting, instilling, investing, misgiving, neglecting, objecting, omitting, oppressing, perfecting, permitting, perplexing, persisting, possessing, predicting, preparing, preventing, professing, progressing, projecting, propelling, prospecting, protecting, reappearing, rebelling, reflecting, refreshing, regretting, rejecting, remitting, repairing, repelling, repressing, requesting, resenting, resisting, respecting, restricting, selecting, subjecting, submitting, subsisting, suggesting, suppressing, suspecting, thanksgiving, transgressing, transmitting, undressing, unerring, unsettling, unsparing, unwilling, unwitting, upsetting
4 Syllables: UUSU
5 Syllables: UUUSU

Found 359 words across 5 groupings. Skipped 24 excess words of a similar stem.