not complex

classic clean elementary modest plain pure uncomplicated

absolute mere rustic single spartan vanilla

austere discreet folksy homely homey humble inelaborate lowly open and shut pure and simple sheer unadorned unadulterated unaffected unalloyed unblended uncombined uncompounded undecorated unelaborate unembellished unfussy unmitigated unmixed unornamented unostentatious unpretentious unqualified

abnormal abstruse complex complicated difficult dirty extraordinary immodest impure indefinite intricate polluted unchaste

aware cluttered convoluted decorated embellished exacting intelligent jumbled mature older on-the-ball ornate smart sophisticated unclear unintelligible