unperceptible

adjective

1. capable of being perceived; recognizable; appreciable: a perceptible change in his behavior.

adjective

1. able to be perceived; noticeable or recognizable

adj.early 15c., “perceptive,” from Late Latin perceptibilis “perceptible,” from Latin percept-, past participle stem of percipere (see perceive). Meaning “capable of being perceived” is from c.1600. Related: Perceptibly; perceptibility.