Vowel /ɪ/ is here spelled <i> in all the syllables which show the contrast. Vowel /з/ is spelled <er>, <ear>, <ir>, <ur> and <or> after <w>. There is also the special case of the German city name Köln.
The difference in length and separation in the mouth make the sounds sufficiently different to obviate any problems for learners.
The only pairs with taboo words are piss/purse and shit/shirt.
Interesting pairs include:
civics cervix
jiminy Germany
The mean density is 1%. The list makes 104 semantic contrasts, giving a loading of 54%.
bid bird bids birds bidden burden big berg bigger burgher Billy Burley bin burn bins burns bitch birch bitched birched bitches birches bitching birching bitten burton biz burrs blitz blurts chill churl chills churls chin churn chinned churned chinning churning chins churns chip chirp chipped chirped chipping chirping chips chirps civics cervix civility servility coition coercion Dick dirk ditty dirty ditties dirties emission immersion emissions immersions fill furl filled furled filling furling fills furls Finnish furnish finish furnish finished furnished finishing furnishing Finn fern Finns ferns fin fern fins ferns fist first fists firsts fizz firs flit flirt flits flirts flitted flirted flitting flirting giggle gurgle giggled gurgled giggles gurgles giggling gurgling gill girl gills girls gym germ gyms germs hid heard hid herd hill hurl hills hurls his hers hiss hearse hisses hearses hit hurt hits hurts hitting hurting id erred ill earl ills earls in earn in urn inn earn inns earns inn urn inns urns inning earning innings earnings is errs Jim germ jiminy Germany kick kirk kicks kirks kid curd kids curds kill curl killed curled killer curler killers curlers killing curling kills curls kiln Koln kiss curse kissed cursed kisses curses kissing cursing kit curt kitten curtain kittens curtains lick lurk licked lurked licking lurking licks lurks lint learnt Lynn learn Mick murk Mickey murky midge merge midges merges Misses mercies missy mercy mitten Merton pick perk picked perked picking perking picks perks pill pearl pills pearls piss purse pissed pursed pisses purses pissing pursing pit pert pitch perch pitched perched pitches perches pitching perching quick quirk quin quern quins querns shit shirt shits shirts shitting shirting sickle circle sickles circles Sid surd sieve serve sieved served sieves serves sieving serving silly surly sillier surlier silliest surliest silliness surliness skiff scurf skill skirl skills skirls skit skirt skits skirts skivvy scurvy slid slurred spin spurn spinning spurning spins spurns spit spurt spits spurts spitting spurting stilling Stirling submission submersion swill swirl swilled swirled swilling swirling swills swirls ticks Turks tiff turf tiffs turfs Tim term tim turn tinned turned tinning turning tins turns tinny tourney tips turps tittle turtle 'twill twirl twilled twirled unbidden unburden Viv verve whim worm whims worms whit wert whiz whirrs wick work wicks works wicker worker will whirl willed whirled willing whirling wills whirls withe worth withies worthies