simple

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