ingenuous

Ingenuous is most often used to describe someone who has a childlike innocence and openness. It should not be confused with ingenious, which typically describes someone who is unusually inventive or clever, or something made or done in an especially original or clever way. The words look very much alike, but sound different: remember that ingenuous sounds like its linguistic relation genuine, while ingenious sounds like genius—despite the fact that there is no etymological connection between those two. For more on this pair, read on.