naif, naive - marked by or showing unaffected simplicity and lack of guile or worldly experience; "a teenager's naive ignorance of life"; "the naive assumption that things can only get better"; "this naive simple creature with wide friendly eyes so eager to believe appearances"

unwary - not alert to danger or deception; "the shrieks of unwary animals taken by surprise"; "some thieves prey especially on unwary travelers"; "seduce the unwary reader into easy acquiescence"- O.J.Campbell