indiscernible

/ˌɪndɪˈsɜrnəbəl/

Other forms: indiscernibly

Indiscernible things can't be seen or sensed clearly. A black cat is indiscernible in the dark, and the tiny amount of gray in your hair might also be indiscernible.

Flavors are indiscernible if you can't taste them, and objects are indiscernible if you can't see them. Your next door neighbor's piano playing is also indiscernible if he plays quietly, with the windows shut so you can't hear. The adjective indiscernible adds the "not" or "opposite of" prefix in- to discernible, from its Latin root discernere, "to set apart," or "to distinguish."

Definitions of indiscernible

1. adjective

   difficult or impossible to perceive or discern
   “an indiscernible increase in temperature”

   antonyms:

   discernible

   perceptible by the senses or intellect
2. adjective

   barely able to be perceived
   “the transition was almost indiscernible”

   synonyms: insensible, undetectable

   imperceptible, unperceivable

   impossible or difficult to perceive by the mind or senses