Synonyms for indiscernible

Adjective

1. indiscernible (vs. discernible)

usage: difficult or impossible to perceive or discern; "an indiscernible increase in temperature"

2. indiscernible, insensible, undetectable, imperceptible (vs. perceptible), unperceivable

usage: barely able to be perceived; "the transition was almost indiscernible"; "an almost insensible change"