Naive (adj) /naɪˈiːv/
Naive definition
willing to trust people excessively – simple and trusting – unsophisticated and unable to analyze matters critically – inexperienced – gullible – credulous – childlike:
Example
That would be so naive to think that this simple plan could eradicate all of our problems.
Antonyms
suspicious, shrewd
Parts of speech
Noun: naivety
Adverb: naively