Côte d’Ivoire· informal
gaou
Meaning
a naive person who is easily fooled
Elsewhere
naïf
Explanation
Standard French has no single word for it; naïf or pigeon come closest. Gaou is Nouchi, the street French of Abidjan.
Example
Méfie-toi de ce vendeur, sinon tu vas passer pour un gaou.
Watch yourself with that seller, or you'll end up looking like a right mug.
Origin
Origin uncertain.
Source