"less discernible" is correct and usable in written English.
You can use it to describe something that is difficult to recognize or perceive due to its small size, lack of color, or low contrast. For example, "The stars in the night sky were less discernible due to the glare of the full moon".
In throughflow mode the regimes were less discernible.
Her old defiance persists, but to far less discernible purpose.
But Bayonne ham is earthier and meatier tasting than its Italian cousin, with less discernible salt.
Overall, certain landscape features were less discernible on the 30-m DEM than on the 10-m DEM.
But where the star ends and the product and pitch begin has grown less and less discernible in the era of the human billboard.
In the era of the human billboard, where the star ends and the product and pitch begin is becoming less and less discernible.
But if the process was the same, the internal motivations for the lawsuit are less discernible--and some former federal civil rights prosecutors insist that such a politically sensitive case had to be vetted by top Justice and White House officials.
It does not present more mature canvases in which the master's influence might be less readily discernible.
The existence of other, less easily discernible biological traits that might have contributed to the extinction of the Neanderthals – such as differences in reproductive rates or developmental histories – cannot be ruled out, but are not supported by current data.
Notably, Goldman treats aesthetic value not as a function of any more or less immediately discernible single property but rather as a complex configurational feature of works.
For Heidegger, however, the "nothing" that is visible in Van Gogh's painting is not the haunting presence of these shoes' absent owner but, instead, the equally paradoxical (and no less phenomenologically discernible) appearance of that which is neither an entity nor merely nothing at all and yet conditions our experience of all entities.
