The spelling of /g/ is <g> or <gg>, and we also see <gu> in fugue and <gh> in ghost. The /m/ sound is spelled <m>, <mm> or <mb> in bomb.
This is a contrast between a stop and a nasal continuant, both voiced but well separated in the mouth. It does not cause any problems.
One mildly taboo word pair is bug/bum. More obviously taboo is shag/sham.
Interesting pairs include:
elegant element
gimmick mimic
haggard hammered
rugger rummer
The figure for the mean density is 2.7%. The set makes 134 semantic contrasts, a loading of 49%.
bog bomb bogged bombed bogging bombing bogs bombs brig brim brigs brims bug bum bugged bummed bugging bumming bugs bums chug chum chugged chummed chugging chumming chugs chums crag cram crags crams dig dim digging dimming digs dims digger dimmer diggers dimmers Doug dumb drag drachm drags drachms drag dram drags drams drug drum drugged drummed drugging drumming drugs drums dug dumb egg M eggs M's elegant element fogey foamy frog from fugue fume fugues fumes gable Mabel gad mad Gael mail Gaels mails Gael male Gaels males gag mag gags mags gain Maine gain main gains mains gait mate gaits mates gale mail gales mails gale male gales males gall mall galls malls gall maul galled mauled galling mauling galls mauls gallows mallows game maim gamed maimed games maims gaming maiming gammon mammon gammy mammy gamy Mamie gangling mangling gap map gaps maps garble marble garbled marbled garbles marbles garbling marbling garter martyr garters martyrs Gary marry gas Mass gases Masses gash mash gassy massy gassier massier gassiest massiest gate mate gates mates gated mated gating mating gat Matt gaud Maud gaudy Maudie Gaul mall Gauls malls Gaul maul Gauls mauls gauze maws gay May gays Mays gay may gaze maize gaze maze gazed mazed gazes mazes gear mere gears meres get met gets Metz gharry marry gharries marries ghee me Ghent meant ghost most ghostly mostly giddy middy gild milled gillie Millie gilt milt gimmick mimic gimmicks mimics girder murder girders murders girth mirth go Mo go mow goes mows going mowing goad mode goads modes goad mowed goal mole goals moles goat moat goats moats gob mob gobs mobs God Mod gods Mods gold Mold gold mould golly Molly goo moo goon moon goons moons goose moose gore more gorse Morse Goth moth Goths moths gourd moored gowned mound guard marred Guildford Milford guile mile Guinean minion Guineans minions gulch mulch gulches mulches gull mull gulled mulled gulls mulls gullet mullet gullets mullets gum mum gums mums gunny money gush mush gust mussed gust must gusts musts gusty musty gustier mustier gustiest mustiest gut mutt gutter mutter guttered muttered guttering muttering gutters mutters guy my guzzle muzzle guzzled muzzled guzzles muzzles guzzling muzzling hag ham hags hams haggard hammered hug hum hugged hummed hugging humming hugs hums jag jam jagged jammed jagging jamming jags jambs jig Jim jig gym jigs gyms lager lama lagers lamas laager lama laagers lamas lag lam lagged lambed lagging lambing lags lambs legging lemming leggings lemmings mag ma'am mug mum mugs mums mugger mummer muggers mummers muggy mummy plug plum plugged plumbed plugging plumbing plugs plumbs prig prim prigs prims rag ram ragged rammed ragging ramming rags rams regain remain regained remained regaining remaining regains remains regnant remnant rig rim rigged rimmed rigging rimming rigs rims rogue Rome rogue roam rogues roams roguish Romish rug rum rugger rummer sag Sam scrag scram scragged scrammed scragging scramming scrags scrams shag sham shagged shammed shagging shamming shags shams shaggy shammy slag slam slug slum slugged slummed slugging slumming slugs slums stagger stammer staggered stammered staggering stammering staggers stammers staggeringly stammeringly staggerer stammerer staggerers stammerers swag swam swig swim swigging swimming swigs swims thug thumb thugs thumbs tog Tom trigger trimmer triggers trimmers unplugged unplumbed Whig whim Whigs whims wig whim wigs whims
John Higgins, Shaftesbury, October 2010.