simple

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