The List
There are 381 6 letter words with I as the first letter. The highest scoring is IZZARD at 25 points in Scrabble. 211 carry three or more vowels, which makes them useful for dumping a vowel-clogged rack.
IAMBICIAMBUSIATRICIBADAHIBADATIBERISIBEXESIBICESIBIDEMIBISESIBRIKSICEBOXICECAPICEMANICEMENICHINGICHORSICICLEICIESTICINGSICKERSICKIERICKILYICKLERICONESICONICIDANTSIDEAEDIDEALSIDEATAIDEATEIDENTSIDIOCYIDIOMSIDIOTSIDLERSIDLESTIDLINGIDOLONIDOLUMIDYLLSIFFIERIFTARSIGAPOSIGGINGIGLOOSIGNAROIGNIFYIGNITEIGNOMYIGNOREIGUANAIHRAMSILEXESILIADSILICESILLESTILLIADILLIPEILLITEILLTHSILLUDEILLUMEILLUPIIMAGEDIMAGERIMAGESIMAGOSIMARETIMARISIMAUMSIMBALMIMBARKIMBARSIMBASEIMBEDSIMBIBEIMBIZOIMBODYIMBOSKIMBOSSIMBREXIMBRUEIMBUEDIMBUESIMIDESIMIDICIMINESIMMANEIMMASKIMMESHIMMEWSIMMIESIMMITSIMMUNEIMMUREIMPACTIMPAIRIMPALAIMPALEIMPARKIMPARLIMPARTIMPAVEIMPAWNIMPEDEIMPELSIMPENDIMPHEEIMPIESIMPINGIMPISHIMPLEDIMPLEXIMPONEIMPORTIMPOSEIMPOSTIMPOTSIMPROVIMPUGNIMPUREIMPUTEINANERINANESINANGAINARCHINARMSINBENTINBORNINBREDINCAGEINCANTINCASEINCAVEINCAVIINCAVOINCEDEINCENTINCEPTINCHEDINCHERINCHESINCISEINCITEINCLESINCLIPINCOGSINCOMEINCONYINCUBIINCULTINCURSINCUSEINDABAINDARTINDEEDINDENEINDENTINDEWSINDIASINDICTINDIESINDIGNINDIGOINDITEINDIUMINDOLEINDOLSINDOORINDOWSINDRISINDUCEINDUCTINDUEDINDUESINDULTINDUNAINERTSINFALLINFAMEINFAMYINFANTINFAREINFECTINFEFTINFELTINFEREINFERSINFESTINFILLINFIMAINFIRMINFLOWINFLUXINFOLDINFORMINFULAINFUSEINGANSINGATEINGENUINGESTINGINEINGLESINGOESINGOTSINGRAMINGRUMINGULFINHALEINHAULINHEREINHOOPINHUMEINIONSINISLEINJECTINJERAINJUREINJURYINKERSINKIERINKINGINKJETINKLEDINKLESINKOSIINKPADINKPOTINLACEINLAIDINLANDINLAYSINLETSINLIERINLOCKINMATEINMESHINMOSTINNAGEINNATEINNERSINNINGINORBSINPOURINPUTSINROADINRUNSINRUSHINSANEINSEAMINSECTINSEEMINSERTINSETSINSHIPINSIDEINSISTINSOLEINSOULINSPANINSTALINSTARINSTEPINSTILINSULAINSULTINSUREINTACTINTAKEINTELSINTENDINTENTINTERNINTERSINTIMAINTIMEINTINEINTIREINTOEDINTOMBINTONEINTORTINTOWNINTRONINTROSINTUITINTURNINTUSEINULASINULININUREDINURESINURNSINVADEINVARSINVENTINVERTINVESTINVITEINVOKEINWALLINWARDINWICKINWINDINWITHINWITSINWORKINWORNINWOVEINWRAPINYALAIODATEIODIDEIODIDSIODINEIODINSIODISEIODISMIODIZEIODOUSIOLITEIONICSIONISEIONIUMIONIZEIONONEIPECACIPPONSIRADESIRATERIREFULIRENICIRIDALIRIDESIRIDICIRISEDIRISESIRITICIRITISIRKINGIROKOSIRONEDIRONERIRONESIRONICIRREALIRRUPTISABELISATINISCHIAISLANDISLETSISLINGISOBARISOGONISOHELISOLEXISOLOGISOMERISOPODISSEISISSUEDISSUERISSUESISTANAISTHMIISTLESITALICITCHEDITCHESITEMEDITERUMITSELFIXODIDIXORASIXTLESIZARDSIZZARDIZZATS