adjective/na.if/
naive, dewy-eyed; gullible
“Il est vraiment naïf, il a gobé tout ce qu'ils lui ont raconté.” — He is really naive; he swallowed everything that they told him.
Inherited from Old French naïf, inherited from Latin nātīvus. Doublet of natif. Semantical shift from "original; natural; simple" to "simple-minded".