Delicate
Faint, Indistinct, Dim
な adjective
The kanji is delicate, and the vocab has this meaning too. It's that kind of "subtle" delicate, not so much that something will break (like it is with the kanji). Something that is a bit faint and indistinct is going to be delicate in this sense, perhaps, too.
If you're going to cuss (かす) up a storm, that's not really being delicate.
彼女の微かな香水の香りに、妙に興奮してしまった。
I got strangely excited by the faint smell of her perfume.