simple

absolute arcadian austere bare barest benighted blockheaded careless chaste childlike classic clean clean cleanest cleanest clear clearer clearest common commonest credulous crude crudest daftest daft dense denser dimwitted doltish dopey doting down to earth downright dull duller dry dupable easiest easy as pie earthy easy effortless easier elegant facile familiar fatuous featherbrained feeble-minded foolish forthright guileless harmless gullible homespun homey homely homelike humblest humblest humble humble ignoble imbecilic imbecile ingenuous innocent 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 natural naive naked 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 primest primitive pure purest readable rudimentary rude rural rustic rustic self-effacing senseless shallower shallow sheer silly simple-minded single slow slower slowest 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