At first, I thought it was a shortened version of ない but recently I entered “very clean plate” into Google Translate and it translated it as “とてもきれいなプレート”. According to my previous theory, it should mean “very not beautiful plate”, but that just doesn’t make sense.
3 comments
It’s not ない. It’s だ copula (present time) in attributive form (な). Slightly similar to how we use am/is/are.
とてもきれいなプレート means “very beautiful plate” and きれいなプレート basically means “plate is beautiful”.
You may want to read about na- adjectives and i- adjectives:
[https://guidetojapanese.org/learn/grammar/adjectives](https://guidetojapanese.org/learn/grammar/adjectives)
>Examples
>
>1. 静か (しずか) **な**人。Quiet person.
>2. きれい**な**人。Pretty person.
きれい – the adjective
な – turns the adjective into a na-adjective. Attributive copula, the attribute being applied to some object.
プレート – the object
​
きれいなプレート – pretty plate.
That is just one use of the particle な.