simple

absolute arcadian austere bare barest benighted blockheaded careless chaste childlike classic cleanest cleanest clean clean clearer clearest clear common commonest credulous crudest crude daftest daft denser dense dimwitted doltish doting dopey down to earth downright dry dull dupable duller easiest easier easy earthy easy as pie effortless elegant facile familiar fatuous featherbrained feeble-minded foolish forthright guileless gullible harmless homespun homelike homely homey humble humble humblest humblest ignoble imbecile imbecilic ingenuous innocent literal loopy low lowly main mere mindless modest modest more familiar more elegant more readable more understandable more modest more modest more natural more primary more primary 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 primary/prime primitive primary primest pure purest readable rudimentary rude rural rustic rustic self-effacing senseless shallow shallower sheer silly simple-minded single slower slowest slow softer softer soft soft softheaded spartan spontaneous stark stupid thick-witted tomfool unaffected unassuming uncomplicated understandable unimposing undiluted unintelligent unoffensive unprocessed unqualified unsuspecting unostentatious unmitigated unpretentious unvarnished unwashed user-friendly unworldly very voluminous virginal