Mammoth Uncensored Word List:
128 words ending with ng, 16 letters long

antiprofiteering antiracketeering autodecrementing autoincrementing chromatographing circumambulating circumnavigating contraindicating counterattacking counterbalancing counterpicketing counterweighting crossmultiplying crosspollinating crossquestioning crossreferencing derequisitioning despiritualizing discomboberating discombobulating discountenancing disenfranchising disequilibrating disproportioning electrophoresing featherstitching hemagglutinating hyperfunctioning hypersensitising hypersensitizing hyperstimulating hyperventilating indiscriminating intercorrelating interinfluencing interpenetrating interstratifying maladministering microengineering microprogramming microstratifying misalphabetizing misappropriating miscommunicating miscomprehending misunderstanding multiprogramming nonbreastfeeding noncommunicating noncomprehending noncrystallizing nondemonstrating nondisqualifying nonincriminating noninterpolating nonmanufacturing nonparticipating nonreciprocating nonsubordinating nonunderstanding operationalising operationalizing overaccentuating overarticulating overcapitalising overcapitalizing overcentralising overcentralizing overcompensating overcomplicating overconstructing overdiversifying overembellishing overexaggerating overgeneralising overgeneralizing overhomogenizing overillustrating overintensifying overmonopolizing overneutralizing overpreoccupying overrepresenting overspecializing photoduplicating photoluminescing photomultiplying photosensitising photosensitizing phototypesetting pinealectomizing preaccommodating preacknowledging precommunicating preconsolidating precontemplating preequilibrating premanufacturing proletarianising proletarianizing radiosensitizing rechoreographing respiritualizing rollercoastering scandalmongering sensationalising sensationalizing sentimentalising sentimentalizing subminiaturizing supercalendering superenciphering supersensitising supersensitizing supersimplifying superstimulating teleconferencing territorializing thermoregulating thoughtprovoking traditionalizing transparentizing underemphasising underemphasizing understimulating undiscriminating undistinguishing weatherstripping