Which word best describes someone who is innocent and simple?

The word "ingenuous" is the most appropriate choice to describe someone who is innocent and simple. It refers to a person who is straightforward, sincere, and naïve, lacking in sophistication or guile. An ingenuous individual often possesses a childlike quality of honesty and openness, making them seem innocent in their views and interactions.

In contrast, "deride" means to mock or ridicule someone, which is entirely opposite to the notion of innocence. "Ingrate" refers to someone who is ungrateful; this does not align with the idea of simple innocence but rather suggests a lack of appreciation. "Compatible" describes how well two things go together, which does not relate to a person’s characteristics of being innocent or uncomplicated. Therefore, "ingenuous" is the term that encapsulates the essence of simplicity and innocence.