Other forms: discerned; discerning; discerns
If you can make out, pick out, or distinguish something, you can discern it. This is a word for recognizing and perceiving things.
Discerning has to do with being able to see or hear something. In a loud room, it can be hard to discern one person's voice. If there's not much light, you'll have trouble discerning the words on a page well enough to read. If you have sloppy handwriting, then it's hard to discern what you wrote. When you can discern something, you can tell what it is; you can identify it.