Not quite sure how to ask this clearly, but I’m looking for the な-adjective equivalent of this い-adjective usage (from the lesson http://www.textfugu.com/season-4/i-adj-conjugation/3-3/#top):
さむい日
Cold day
さむかった日
Day that was cold
あつい日
Hot day
あつかった日
Day that was hot
So, I’m not looking for, for example:
くるま は あんぜん でした
The car was safe
I’m also not looking for this:
あんぜんな くるま は 。。。でした
The safe car was
I’m looking for the correct way to say something like this:
あんぜんな (?)くるま は 。。。
The car that was safe…
I hope my question makes some semblance of sense.