Do you use shiniest or most shiny in sentences?

"Shiniest" is the superlative form of "shiny," meaning it's used to compare three or more things and indicate the one with the highest degree of shininess. "Most shiny" is also grammatically correct, but less common, and generally considered slightly less elegant.

Therefore, you'd use "shiniest" in most cases. However, "most shiny" might be preferred in certain contexts where it sounds more natural or emphasizes a particular aspect of shininess (though this is subjective).

Examples:

* Shiniest: "Of all the apples, this one is the shiniest."

* Most shiny: "This apple has the most shiny surface." (Slightly awkward, "shiniest" is better here)

In short, while both are grammatically possible, "shiniest" is the generally preferred and more concise option.