WordWeb Online

1. Perceptible by the senses or intellect
   "the newspaper reports no discernible progress in the negotiations"; "the skyline is easily discernible even at a distance of several miles"; "things happen in the earth and sky with no discernible cause";
   - discernable
    
2. Capable of being perceived clearly
   "an essay with a meaning that was not always discernible"
    
3. Capable of being seen or noticed
   "a discernible change in attitude";
   - evident, observable

See also: noticeable, perceptible

Antonym: indiscernible