simple

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