simple

absolute arcadian austere barest bare benighted blockheaded careless chaste childlike classic clean clean cleanest cleanest clear clearest clearer commonest common credulous crude crudest daftest daft denser dense dimwitted doltish dopey doting down to earth downright dry dull duller dupable easiest easier earthy easy as pie easy effortless elegant facile familiar fatuous featherbrained feeble-minded foolish forthright guileless gullible harmless homelike homely homespun homey humble humble humblest humblest ignoble imbecile imbecilic innocent ingenuous literal loopy low lowly main mere mindless modest modest more elegant more familiar more modest more modest more natural more readable more primary more primary more understandable more virginal most primary most primary most virginal naive naked natural nominal nothing to it nothing to it oafish open-and-shut open and shut/open-and-shut ordinary oversimplified pastoral pellucid perfect plain plain primest primary primary/prime primitive pure purest readable rudimentary rude rustic rustic rural self-effacing senseless shallow shallower sheer silly simple-minded single slow slower slowest soft soft softer softer spartan softheaded spontaneous stark stupid thick-witted tomfool unaffected unassuming uncomplicated understandable undiluted unimposing unintelligent unoffensive unostentatious unmitigated unprocessed unpretentious unqualified unsuspecting unwashed unworldly unvarnished user-friendly very virginal voluminous