WordNet sense 1 (not wise in the ways of the world):

unsophisticated

WordNet sense 2 (lacking in sophistication or worldliness):

ingenuous, innocent

WordNet sense 3 (naive and easily deceived or tricked):

green, gullible

WordNet sense 4 (showing a lack of judgment or experience):

credulous

WordNet sense 5 (exhibiting childlike simplicity and credulity):

simple

WordNet sense 6 (marked by or showing unaffected simplicity and lack of guile or worldly experience):

naif

WordNet sense 7 (of or created by one without formal training; simple or naive in style):

primitive

WordNet sense 8 (not disciplined or conditioned or made adept by training):

untrained

WordNet sense 9 (not established by conditioning or learning):

innate, unconditioned, unlearned

WordNet sense 10 (lacking information or instruction):

unenlightened, uninstructed

WordNet sense 11 (not informed; lacking in knowledge or information):

uninformed

WordNet sense 12 (not initiated; deficient in relevant experience):

uninitiated, uninitiate

WordNet sense 13 (lacking practical experience or training):

inexperient