Simple-minded
Part of speech: adjective
Definition: Lacking subtlety or sophistication Lacking mental capacity; feeble-minded
Naif
Part of speech: adjective
Definition: Naïve.
Part of speech: noun
Definition: One who is naïve.
Simple-minded as an adjective is lacking subtlety or sophistication while Naif as an adjective is naïve.
Part of speech: adjective
Definition: Lacking subtlety or sophistication Lacking mental capacity; feeble-minded
Part of speech: adjective
Definition: Naïve.
Part of speech: noun
Definition: One who is naïve.
We hope you now know whether to use Simple-minded or Naif in your sentence.