diaphanous

läpikuultava transparent Transparent or translucent; allowing light to pass through; capable of being seen through.
1899, Joseph Conrad, s:Heart of Darkness|Heart of Darkness, s:Heart of Darkness/Section I|section 1

The water shone pacifically; the sky, without a speck, was a benign immensity of unstained light; the very mist on the Essex marsh was like a gauzy and radiant fabric, hung from the wooded rises inland, and draping the low shores in diaphanous folds.

But nonetheless the purpleness of the imagined purple cow will almost certainly be meaner, more diaphanous, more fleeting than any real-life purple that you ever saw: to imagine a purple cow is just not the same thing as to have a purple sensation (or at least a purple sensation worth the name).

The evening mist, drifting among the leafless poplars, veiled their silhouettes with a violet film, paler and more translucent than the most diaphanous gauze that might have caught in their branches.

The most diaphanous wings carry a burden of pollen from flower to flower.

What is amazing is that "a concept that is created by mind itself, the sequence of integers, the simplest and most diaphanous thing for the constructive mind, assumes a similar aspect of obscurity and deficiency when viewed from the axiomatic angle" (Weyl, 1963, 220).