having or showing unaffected simplicity of nature or absence of artificiality; unsophisticated; ingenuous.

having or showing a lack of experience, judgment, or information; credulous

She's so naive she believes everything she reads. He has a very naive attitude toward politics.

having or marked by a simple, unaffectedly direct style reflecting little or no formal training or technique

valuable naive 19th-century American portrait paintings.

not having previously been the subject of a scientific experiment, as an animal.