naive 

adjective

1. (of a person or action) showing a lack of experience, wisdom, or judgment.

   "the rather naive young man had been totally misled"

   • (of a person) natural and unaffected; innocent.

     "Andy had a sweet, naive look when he smiled"

     Similar:

     innocent

     unsophisticated

     artless

     ingenuous

     inexperienced

     guileless

     unworldly

     childlike

     trusting

     trustful

     dewy-eyed

     starry-eyed

     wide-eyed

     fond

     simple

     natural

     unaffected

     unpretentious

     gullible

     credulous

     easily taken in

     easily deceived

     unsuspecting

     over-trusting

     over-trustful

     born yesterday

     unsuspicious

     deceivable

     dupable

     immature

     callow

     raw

     green

     as green as grass

     ignorant

     wet behind the ears

     Opposite:

     sophisticated

     disingenuous

     experienced

     worldly
   • of or denoting art produced in a straightforward style that deliberately rejects sophisticated artistic techniques and has a bold directness resembling a child's work, typically in bright colors with little or no perspective.